# Viability of RAID, long term



## hat (Jul 17, 2021)

Have a read and see if my logic is sound... or point out any flaws...

I'm beginning to gather some data that's important-ish to me and I'd rather not lose it. So, rather than storing it on a single drive, I'd like to employ RAID. RAID5 seems like a good option, but I'm still rolling the dice on running into a URE if I ever have to rebuild the array should a drive fail. RAID1, or RAID10, doesn't have this issue, but all types of RAID do share one issue: a controller fault. Should the controller fail, you're still screwed, regardless of disk health, unless you can find the same controller again. This is data I'm going to keep around indefinitely, so I'm planning on _something_ to fail... else I wouldn't be considering RAID.

So, either way, something will fail and I'll be screwed. I guess this is why they say "RAID is not a backup!". In order to mitigate this, I would hazard a guess that a single external drive matching the size of my array should be an acceptable solution. Of course, this still doesn't work in the "somebody bombed my house" scenario, or in the astronomically unlikely event that both the RAID and the external totally fail at once, but I'm not thinking that extreme. This way, RAID5 should still be acceptable, even if I should run into a URE, as the data will be recoverable elsewhere. The loss of the RAID controller itself also isn't the end of the world.


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## eidairaman1 (Jul 17, 2021)

Id have a backup setup that is put away in a firebox (drives/discs) at lowest level and highest level a raid/usb/flashdrive.

Id use a external raid card unless if you intend on swapping motherboards when they fail.


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## lexluthermiester (Jul 17, 2021)

RAID 5 is a good way to keep data from being lost. RAID 6 provides even more redundancy at the cost of overall storage space. In general practical applications, RAID 5 requires a minimum of 3 identical drives to function(at a cost of 1 drive capacity for parity and striping functions) and RAID 6 requires 6(with capacity loss of 2 drives for parity and striping data). With RAID 5 you have fault tolerance of 1 drive. With RAID 6 you have a fault tolerance of 2 drives.

Each of those options makes for a good way to store data long term that is available quickly and with fast access times at a moments notice.

A external RAID box, or RAID enabled NAS are also solid options.

However, you should also consider a non-HDD/SSD solution for data backups if instant access is not required.

MDisc Bluray recordable. Available in capacities upto 100GB. It's slower but is infinitely expandable and it also less(in many cases MUCH less) expensive on a per GB cost comparison, depending on the HDD/SSD options you're considering.


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## claes (Jul 17, 2021)

RAID really isn’t a backup, and with backblaze being so cheap these days I don’t know why everyone doesn’t use it or similar services.

More, if you’re going to build a RAID, always buy an extra disk. All disks fail eventually, and usually at the same time (assuming the array is made up of the same disk). Once one disk in an array fails it’s only a matter of time before the whole array does. The extra disk is a stopgap for you to move your data somewhere else (which begs the question, why not RAID6 for your use, but that’s an aside).

To get to your concern, most RAID AICs use the same couple of controllers and can often be flashed to other firmwares. You can often swap an array between cards if a) they use the same firmware (different models/controllers across LSI for example) or b) if they use the same controller and you flash to the appropriate firmware (Dell to LSI with same controller). The metadata is on the disks in the array, but, you know — always read the manual. I wouldn’t be surprised if the metadata is the same across vendors and they’re all just swappable, but I’ve never tried.

Finally, because the technology is so ubiquitous and there are so few vendors, you can often find a backup on eBay, or even new. The h700 I bought a decade ago is still the same price on eBay, and the 9750-4i I bought even longer ago for ~$250 new is now ~$125 new, ~$30 used.


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## Blue4130 (Jul 17, 2021)

What is your use case? Is this just a home machine with family photos and such? Do you need the uptime of raid? 

For many people, they dont. Many would be better served with a large international drive and an off site backup. Use two drives in rotation for the backup, updating depending on how often you add data. (or a single backup drive and a copy of backblaze or Amazon glacier)


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## OneMoar (Jul 17, 2021)

EVERYBODY SAY IT WITH ME
*RAID
IS
NOT
A
BACKUP*


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## Solaris17 (Jul 17, 2021)

OneMoar said:


> EVERYBODY SAY IT WITH ME
> *RAID
> IS
> NOT
> ...



gonna quote it for those in the back.

also raid 5 and 6 are terrible. Anyone who says otherwise does not have experience with it at any kind of scale. Consumer drives in raid 5 or 6 will also likely be a faster way to lose your data than a single drive.

raid 1 or 10. though with back blaze being so cheap why someone would want to risk data on something that ISNT a backup while running raid 5 at home is beyond me.

seriously reconsider your options.


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## thesmokingman (Jul 17, 2021)

lexluthermiester said:


> RAID 5 is a good way to keep data from *being lost.* RAID 6 provides even more redundancy at the cost of overall storage space. In general practical applications,


Ugh... RAID is not a way to keep data from being lost. That would be a backup. RAID is for availability, uptime. Maybe it's just your wording cuz you use the right term redundancy....



Solaris17 said:


> gonna quote it for those in the back.
> 
> also raid 5 and 6 are terrible. Anyone who says otherwise does not have experience with it at any kind of scale. Consumer drives in raid 5 or 6 will also likely be a faster way to lose your data than a single drive.
> 
> ...


This.


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## OneMoar (Jul 17, 2021)

Raid for availability cloud backup for retention preferably with a periodic offline backup


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## claes (Jul 17, 2021)

Solaris17 said:


> also raid 5 and 6 are terrible. Anyone who says otherwise does not have experience with it at any kind of scale. Consumer drives in raid 5 or 6 will also likely be a faster way to lose your data than a single drive.


I agree with the rest of your post, but I’m not so sure about this part. Why are you arguing that RAID 5/6 is less reliable than 0/1?

When I was in undergrad I built RAID systems for AV up-and-comers (thousands of systems) using consumer disks to great effect. This was a little more than a decade ago and, AFAIK*, >90% haven’t had a disk failure. IME, 0/1 is less reliable than 5/6, largely due to the number of disks, but it really depends on the use case.l, and I’m curious to hear about yours!

I mean that if, you’re talking about write-intensive conditions, like maintaining a fast database or similar then, sure, RAID0/1 is preferable (and begs for an off-site backup). But for more common use cases/shared environments, IME, RAID5+ is pretty reliable. It sounds like yours differs (or not?), and am curious to hear more!

Regarding OP, I think it’s clear that consensus is with the 3-2-1 backup scenario (I assume you’re familiar, but please say so if not!)... I think RAID5 is fine for “reliable” mass storage, but it really depends on your use and, still, RAID is not a backup — it’s just postponing the inevitable.


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## TheLostSwede (Jul 17, 2021)

Have you considered something like SnapRAID, which technically isn't RAID at all.





						SnapRAID
					

A backup program for disk arrays. It stores parity information of your data and it recovers from up to six disk failures



					www.snapraid.it
				




I use it on my NAS instead of traditional RAID, in combination with UnionFS, but it also works on Windows.
The trade-off is that you don't get the performance of say RAID-5, since the drives are operating as single drives, but you get parity data, data integrity and snapshots,
It also claims to be more failure tolerant, but luckily I haven't had to try that as yet.
It's also much easier to expand than RAID.

In all fairness, I still back up all the data to an external drive, just in case.


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## Ahhzz (Jul 17, 2021)

Absolutely what those above have said: RAID is for availability, not backup. I've found a local NAS is good, especially when augmented by Dropbox (I've got 20Gb there. choose your low-cost poison: GDrive, OneDrive, w/e), but RAID is availability.


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## mb194dc (Jul 17, 2021)

OneMoar said:


> EVERYBODY SAY IT WITH ME
> *RAID
> IS
> NOT
> ...



Yup, those of us who've had double disk failures in the past can attest to that...! 

Even keeping all data in one physical location is a risk. Google or other cloud storage is the way, though then security of the data needs to be taken in to account. 

You're trusting Google to manage their servers and data centres properly but it's the best you can do for a reasonable cost.


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## nguyen (Jul 17, 2021)

I just buy new SSD every 2 years when they double the capacity for the same price, bought a 512GB from 6 years back, 1TB from 4 years back and 2TB 2 years ago, all for the same dough.
I do the same for NAS too


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## DrCR (Jul 17, 2021)

hat said:


> Have a read and see if my logic is sound... or point out any flaws...
> 
> I'm beginning to gather some data that's important-ish to me and I'd rather not lose it. So, rather than storing it on a single drive, I'd like to employ RAID. RAID5 seems like a good option, but I'm still rolling the dice on running into a URE if I ever have to rebuild the array should a drive fail. RAID1, or RAID10, doesn't have this issue, but all types of RAID do share one issue: a controller fault. Should the controller fail, you're still screwed, regardless of disk health, unless you can find the same controller again. This is data I'm going to keep around indefinitely, so I'm planning on _something_ to fail... else I wouldn't be considering RAID.
> 
> So, either way, something will fail and I'll be screwed. I guess this is why they say "RAID is not a backup!". In order to mitigate this, I would hazard a guess that a single external drive matching the size of my array should be an acceptable solution. Of course, this still doesn't work in the "somebody bombed my house" scenario, or in the astronomically unlikely event that both the RAID and the external totally fail at once, but I'm not thinking that extreme. This way, RAID5 should still be acceptable, even if I should run into a URE, as the data will be recoverable elsewhere. The loss of the RAID controller itself also isn't the end of the world.


For me, raid 6 via mdadm on Ubuntu Server. Separate drive that has data backed up to it via daily rsnapshot. And a cold storage drive occasionally connected and rsnapshot to as well. Never have gone down a cloud path.

zfs is next level though (avoids bit rot) if you're willing to invest the time to learn it.


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## Aquinus (Jul 17, 2021)

Solaris17 said:


> also raid 5 and 6 are terrible. Anyone who says otherwise does not have experience with it at any kind of scale. Consumer drives in raid 5 or 6 will also likely be a faster way to lose your data than a single drive.


I've had RAID-5 in my tower since I first built it with the 3820 and I've never had a full RAID failure with WD Blacks. I never lost the entire array and it had become degraded from actual disk failures a handful of times. So, my experience is actually quite different than what you're implying.

With that said though, RAID is not a backup, it's to mitigate unnecessary downtime. You still need to keep a backup of your data regardless of the RAID type you use because they all can fail, or worse, your house could burn down and no raid level RAID will help you there.


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## Solaris17 (Jul 17, 2021)

claes said:


> I mean that if, you’re talking about write-intensive conditions, like maintaining a fast database or similar then, sure, RAID0/1 is preferable (and begs for an off-site backup). But for more common use cases/shared environments, IME, RAID5+ is pretty reliable. It sounds like yours differs (or not?), and am curious to hear more!


Hi! This thread really isn’t the place but we have multiple locations (tens of thousands of disks) big arrays as in many disks are the most susceptible but if the disks are also large in size the rebuild time and possibly of a URE or another failed disk is very high. These two levels do not scale well with size both physically or data wise. It is not always data at play, a cache chip or other physical issue can cause a drive to fail that may not be registered in SMART and a rebuild taxes other disks greatly. Smaller arrays are bad as well but easier to handle with the right disks. I think maybe the biggest difference in our experiences is the March of time. There are multiple disk “models” that are “meant for X” now. Data creep is also always on the rise, so array sizes may be a lot larger now than what you used. See below.



Aquinus said:


> I've never had a full RAID failure with WD Blacks. I never lost the entire array and it had become degraded from actual disk failures a handful of times


Not much to say to this other than it kind of proves my point. “My disks have failed multiple times” is not a great argument FOR using these raid types or consumer drives.

it’s not a competition to see how many drives fail and each occurrence is a huge risk.


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## TheLostSwede (Jul 17, 2021)

Aquinus said:


> I've had RAID-5 in my tower since I first built it with the 3820 and I've never had a full RAID failure with WD Blacks. I never lost the entire array and it had become degraded from actual disk failures a handful of times. So, my experience is actually quite different than what you're implying.
> 
> With that said though, RAID is not a backup, it's to mitigate unnecessary downtime. You still need to keep a backup of your data regardless of the RAID type you use because they all can fail, or worse, your house could burn down and no raid level RAID will help you there.


Just curious, how many hours did it take to rebuild after you lost a drive?


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## registertotypetostrangers (Jul 17, 2021)

hat said:


> but all types of RAID do share one issue: a controller fault.


Sure, but thats why you wouldn't use a raid system that relies on a hardware raid controller.   Plenty of software raid solutions these days for home to enterprise use cases that don't rely on proprietary setups.   

I personally recommend a ZFS based raid solution like Truenas for redundancy and portability.  Truenas pools do not care how or where the storage devices are attached just as long as the system can see the disks, making transporting the array to a new system or HBA as easy as a few clicks of a mouse button.


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## newtekie1 (Jul 17, 2021)

hat said:


> RAID5 seems like a good option, but I'm still rolling the dice on running into a URE if I ever have to rebuild the array should a drive fail. RAID1, or RAID10, doesn't have this issue


Uh, RAID1 and RAID10 definitely do have an issue of URE during a rebuild.



hat said:


> all types of RAID do share one issue: a controller fault. Should the controller fail, you're still screwed, regardless of disk health, unless you can find the same controller again.


You ususally don't have to find the same controller, just one from the same company.  If you use Intel's built in RAID for example, you can connect the drives to any motherboard with an Intel RAID controller(as long as it supports the RAID type you use) and the array will be usable.


hat said:


> I would hazard a guess that a single external drive matching the size of my array should be an acceptable solution.


Yep, that's a good plan. An offsite backup would be even better, but that can get a little on the pricey side, and backing up tens of TB of data over a slow internet connection isn't fun.


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## lexluthermiester (Jul 17, 2021)

My experience with RAID seems to have been much better than those who have bemoaned and complained of it. I used RAID consistently for nearly 2 decades. First with SCSI then IDE followed by SATA and SAS. I'm not personally using RAID currently as BDR fits my data redundancy needs.


OneMoar said:


> EVERYBODY SAY IT WITH ME
> *RAID
> IS
> NOT
> ...


Thanks for the tip Mr Craft. Not only is such a statement functionally incorrect, it is historically incorrect. RAID was a concept made in a time when backups were either very expensive or very slow and often both. RAID solved a number of problems all at once. It allowed for high capacity, high speed storage that had data redundancy built into the functionality scheme. And for the record, RAID 10, 50 and 60 for examples are, BY DEFINITION, forms of backups. For those of you who fail to understand this, some reading and research is in order.

Everybody say it with me:
*R*edundant
*A*rray of
*I*nexpensive
*D*isks

The ONLY form of RAID that does NOT have data redundancy built in to it is RAID 0(JBOD does not count as an actual RAID form, it's more of an afterthought). ALL other forms of RAID have data redundancy built into them. RAID was originally designed to be a form of data storage that could be maintained on an ongoing basis without the need for supplementary backups, effectively storage and backup rolled into one. With modern drives being IMMENSELY more reliable than drive of the time when RAID was created. Current RAID arrays, even when created using budget drives, are very reliable. However because of the advent of modern backups available, RAID has(ironically) become a somewhat expensive endeavour, comparatively.

As for the idea that a RAID controller is a point of weakness, they are not. RAID controllers fail extremely rarely.

RAID is still a *very reliable* form of data storage, even when used as a backup. Anyone who states otherwise is expressing an opinion NOT supported by history, evidence or effective practical application of the technology.


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## eidairaman1 (Jul 17, 2021)

lexluthermiester said:


> My experience with RAID seems to have been much better than those who have bemoaned and complained of it. I used RAID consistently for nearly 2 decades. First with SCSI then IDE followed by SATA and SAS. I'm not personally using RAID currently as BDR fits my data redundancy needs.
> 
> Thanks for the tip Mr Craft. Not only is such a statement functionally incorrect, it is historically incorrect. RAID was a concept made in a time when backups were either very expensive or very slow and often both. RAID solved a number of problems all at once. It allowed for high capacity, high speed storage that had data redundancy built into the functionality scheme. And for the record, RAID 10, 50 and 60 for examples are, BY DEFINITION, forms of backups. For those of you who fail to understand this, some reading and research is in order.
> 
> ...



Might as well have a hard back up of optical discs, tapes/flash drives kept in a vaccum box that is protected from extreme heat/light/humidity and is shielded in lead. And connector ends protected.


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## newtekie1 (Jul 17, 2021)

lexluthermiester said:


> And for the record, RAID 10, 50 and 60 for examples are, BY DEFINITION, forms of backups.



Not they aren't.  The definition of a backup is "a copy of computer data". Redundancy from a drive failure alone does NOT fit even that very basic definition of a backup as the data isn't actually copied.

You might be able to make the argument that RAID 1 is a backup with that very basic definition, as the mirroring could be considered a copy of the data.  But any RAID method that uses parity definitely doesn't fit the definition of a backup at all. And I'd argue that RAID 1 isn't a backup either for reasons stated below.


lexluthermiester said:


> RAID is still a *very reliable* form of data storage, even when used as a backup. Anyone who states otherwise is expressing an opinion NOT supported by history, evidence or effective practical application of the technology.


Yes, RAID(with the exception of RAID0) is a very reliable form of data storage. Certainly more reliable than a single drive.  That's the point.  However, it is not a backup and shouldn't be considered one. Having the mindset that RAID is a backup is a dangerous thing. And I've personally seen it burn people in the past.

The very basics of a backup should have two copies of the data, this protects against more than just a hardware failure. It protects against human error(or software issues) that damages files. This is an important function of a backup that RAID does not do and is why...say it with me now...*RAID IS NOT A BACKUP*.


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## lexluthermiester (Jul 17, 2021)

newtekie1 said:


> Not they aren't.


Yes, they are. RAID 10, 50 and 60 all create multiple sets of the data stored in the array. Should a disk in one of those sets fail, the BACKUP set(or sets) allows continued access until the fault is corrected with a replacement drive. By it's very construct and definition these forms of RAID are realtime, in-use backups. Anyone who fails to understand this very simple concept is in need of further education.



newtekie1 said:


> Not they aren't. The definition of a backup is "a copy of computer data". Redundancy from a drive failure alone does NOT fit even that very basic definition of a backup as the data isn't actually copied.
> 
> You might be able to make the argument that RAID 1 is a backup with that very basic definition, as the mirroring could be considered a copy of the data. But any RAID method that uses parity definitely doesn't fit the definition of a backup at all. And I'd argue that RAID 1 isn't a backup either for reasons stated below.


You are making a great many assumptions about how RAID arrays are used. Just because some do not use RAID in such a capacity or view it as such does NOT make it any less a valid option as a form of data redundancy and backup.



newtekie1 said:


> say it with me now...*RAID IS NOT A BACKUP*.


You can say that till the Sun stops shining, it will not make such a statement correct. Such an opinion is not supported by historical and current industry-wide usage models.


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## OneMoar (Jul 17, 2021)

lexluthermiester said:


> Yes, they are. RAID 10, 50 and 60 all create multiple sets of the data stored in the array. Should a disk in one of those sets fail, the BACKUP set(or sets) allows continued access until the fault is corrected with a replacement drive. By it's very construct and definition these forms of RAID are realtime, in-use backups. Anyone who fails to understand this very simple concept is in need of further education.
> 
> 
> You are making a great many assumptions about how RAID arrays are used. Just because some do not use RAID in such a capacity or view it as such does NOT make it any less a valid option as a form of data redundancy and backup.
> ...


if a RAID array Is your only data backup then you are doing it wrong full stop
Raid Controllers fail all the time backplanes fail all the time power supplies can nuke entire 12 disk arrays, not to mention acts of nature or theft

No raid is not a backup it should never be treated as a backup* I don't care how many morons on the planet try and use it that way they are all wrong and stupid
thats right if you do this and support doing it in any scenario except maybe a massive data center with 50 drives in a cluster  your a fking moron and should have your pocket protector revoked 
I have seen this exact kind of blatant disregard for data safety nearly sink business twice in the last year *

nobody and I repeat nobody ever uses the Odd raid levels its cost/storage capacity  probative todo and thus not common

we aren't talking about data centers where we have racks of 30 drives all in a redundant array with offsite backup

but hey even if we where look what happened to OVH they are major player and a bunch of people lost data and I bet my socks it was running in a massive array with No offsite backup because hey bad things never happen

my statement is very correct there is simply a epidemic of poor data retention policy's in the industry and catastrophe happens everyday because of it

too many people putting there faith that the unthinkable can't happen well it happens A LOT Actually and usually at the worst possible time

you think you are so smart and everybody is as smart as you and would never ever ever put two drives in a Raid 1 with there entire company data on it and no offsite backup
you are very very wrong and need to spend some time in the real working IT world especially on the Small business s side the shit I have seen gives me nightmares, the shit I have done reserved me a spot in hell


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## lexluthermiester (Jul 17, 2021)

OneMoar said:


> No raid is not a backup it should never be treated as a backup* I don't care how many morons on the planet try and use it that way they are all wrong and stupid
> thats right if you do this and support doing it in any scenario except maybe a massive data center with 50 drives in a cluster your a fking moron and should have your pocket protector revoked
> I have seen this exact kind of blatant disregard for data safety nearly sink business twice in the last year *


Nerve, meet hammer..


OneMoar said:


> you think you are so smart


The word "think" is an interesting choice of vocabulary.


OneMoar said:


> and everybody is as smart as you and would never ever ever put two drives in a Raid 1 with there entire company data on it and no offsite backup


True. I would never recommend that particular scenario for a business entity unless an alternate form of supplemental backup is employed. However, RAID 1 is an excellent way to protect from data loss for workstations and end-users. It is a valid form of realtime backup because if a drive fails, you have a backup of all your data on the other drive(s). Again, the very definition of "backup".


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## Solaris17 (Jul 17, 2021)

Lot wrong with this thread.

RAID is not a backup. I’m not even sure how this is a conversation other than speaking to the willfully ignorant.

this is the same level of stupid as the dude who went around saying you shouldnt have backups last year.

the other disks in a RAID are not backups. They are drives that work together to form a SINGLE volume, regardless of RAID level.

these disks do NOT work independently in any fashion. Unlike a backup, which is a copy not reliant on the source.

to preach otherwise shows a serious lack of technical understanding and is dangerous and damaging to those that want to understand and graduate into higher technology.

in raid a silent failure of one drive, or a virus for example will happily replicate that corruption to all the other disks.

if you cannot see how this loss of data itself excludes RAID as a backup option then there isn’t much hope left.

we can only hope the OP and other can understand.


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## Grog6 (Jul 17, 2021)

I have 2 10TB arrays I use for video storage; I've lost drives over the years, but was able to swap and rebuild easily.
I have 3x 45 drive raid 5 scsi drives I use for video editing on my dual processor server I got for $139 .  
If you have things you dont want to lose to a drive failure, I'd recommend raid 5 at a minimum.
These drives got built in 2005, so I think it works pretty well.
I've failed a wd drive and a maxtor drive, both were over 10 years old when they died.


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## lexluthermiester (Jul 17, 2021)

Solaris17 said:


> Lot wrong with this thread.
> 
> RAID is not a backup. I’m not even sure how this is a conversation other than speaking to the willfully ignorant.
> 
> ...


These are opinions based on a particular perspective & set of experiences and you are welcome to them.. Not everyone agrees. As demonstrated by the discussion here, there are MANY schools of thought on the subject of the term "backup"..


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## newtekie1 (Jul 17, 2021)

lexluthermiester said:


> Yes, they are. RAID 10, 50 and 60 all create multiple sets of the data stored in the array. Should a disk in one of those sets fail, the BACKUP set(or sets) allows continued access until the fault is corrected with a replacement drive. By it's very construct and definition these forms of RAID are realtime, in-use backups. Anyone who fails to understand this very simple concept is in need of further education.


First of all, with the exception of RAID 10, none of those create multiple sets of data. They use parity which is not a 2nd set of the data.

RAID 10 uses Mirroring at least, which fits the loosest definition of backup, which I provided.  But then it is using striping on top of that, which reduces the redundancy.



lexluthermiester said:


> You are making a great many assumptions about how RAID arrays are used. Just because some do not use RAID in such a capacity or view it as such does NOT make it any less a valid option as a form of data redundancy and backup.


No, you are claiming that RAID by definition is a form of backup. I gave you the definition of backup, and RAID doesn't fit it(again with the arguable exception of RAID 1).


lexluthermiester said:


> True. I would never recommend that particular scenario for a business entity unless an alternate form of supplemental backup is employed. However, RAID 1 is an excellent way to protect from data loss for workstations and end-users. It is a valid form of realtime backup because if a drive fails, you have a backup of all your data on the other drive(s). Again, the very definition of "backup".


Nope, not the definition of a backup. Again, I posted the definition of backup. Unless you have some other official source of the definition, stop saying RAID fits the definition.

But just in case, lets go ahead and do a Google search for Backup and see what we come up with in the first 5 hits:


Merriam-Webster's Definition of Backup:  a copy of computer data (such as a file or the contents of a hard drive)
Nope, RAID doesn't fit that definition.

Dictionary.com's Definition of Backup: a copy or duplicate version, especially of a file, program, or entire computer system, retained for use in the event that the original is in some way rendered unusable.
Nope, RAID doesn't fit that definition.

Cambridge Dictionary's Definition of a Backup: a copy of information held on a computer that is stored separately from the computer
Nope, RAID doesn't fit that definition.

Wikipedia's Definition of a Backup: a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event.
Nope, RAID doesn't fit that definition.

Macmillian Dictionary's Definition of a Backup: a copy of information on your computer that you make in case you lose the information
Nope, RAID doesn't fit that definition.

So you keep saying RAID is the very definition of "backup" but I'd like to know what definition of backup you are using, because it doesn't fit a single one of these.  RAID is not a copy of the data.  It does not allow you to restore data that was lost from the primary storage location. That is the very definition of backup, and RAID doesn't fit it.  There is no more need to discuss this, you are wrong and the information you are giving is incorrect and frankly dangerous for people's data.



lexluthermiester said:


> You can say that till the Sun stops shining, it will not make such a statement correct. Such an opinion is not supported by historical and current industry-wide usage models.


Nope. Current industry usage models do not treat RAID as a backup. I know, I'm in the industry, I work with data center servers every day.  RAID is a layer of protection for data, it is not a backup.

As I explained a backup protects against more than just a storage drive failure. It is real easy to determine if something is a backup. If you can delete a file from the main data location, and then recover that file from the 2nd data location, that 2nd data location is a backup. You can't do that with a RAID, so...say it with me now...*RAID IS NOT A BACKUP*.


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## lexluthermiester (Jul 17, 2021)

newtekie1 said:


> First of all, with the exception of RAID 10, none of those create multiple sets of data. They use parity which is not a 2nd set of the data.
> 
> RAID 10 uses Mirroring at least, which fits the loosest definition of backup, which I provided. But then it is using striping on top of that, which reduces the redundancy.


Do review...





						RAID Types (Levels) Reference
					

RAID levels reference covers various aspects and tradeoffs of the different RAID levels.



					www.raid-calculator.com
				








						Nested RAID levels - Wikipedia
					






					en.wikipedia.org
				



You were saying?


newtekie1 said:


> I gave you the definition of backup


YOUR definition of backup, not everyone else's...








						What is Data Backup? - Definition from Techopedia
					

This definition explains the meaning of Data Backup and why it matters.




					www.techopedia.com
				





> while RAID, or mirror, technologies provide automated backup options.








						Backup - Wikipedia
					






					en.wikipedia.org
				





newtekie1 said:


> Nope.


Yup.


newtekie1 said:


> Current industry usage models do not treat RAID as a backup.


Opinion.


newtekie1 said:


> I know, I'm in the industry,


So am I and in two differing capacities.


newtekie1 said:


> I work with data center servers every day.


Yup, right there too.


newtekie1 said:


> RAID is a layer of protection for data, it is not a backup.


Do you see what you did there? You contradicted yourself. Providing a layer of protection for data through *data duplication*, which is what most forms of RAID do, *is the exact same thing as making a backup*. Making multiple copies of data for the purpose of protecting against data lost is literally making backups! This is not a difficult concept to understand. And yet, here we are...

We could go on like this for days and those claiming RAID is not a form of backup will continue to argue their point and those who correctly understand the application and purpose of RAID will continue to point out how that perspective contradicts common knowledge and understanding. We're not going to succeed in convincing each other, so..

Naysayers, do have your last words let's be done here...


----------



## thesmokingman (Jul 17, 2021)

Solaris17 said:


> Lot wrong with this thread.
> 
> RAID is not a backup. I’m not even sure how this is a conversation other than speaking to the willfully ignorant.
> 
> ...


No sense debating with him. He doesn't understand the difference between uptime and backup.


----------



## OneMoar (Jul 17, 2021)

lexluthermiester said:


> Do review...
> 
> 
> 
> ...


No data duplication is not the same thing as a backup Your trying to equate live working copy with `backup` those are NOT AND NEVER SHOULD BE THE SAME THINGS
no so long as one or more is true
A. Part of the Same VOLUME as the primary data source
B. Electronically or physically connected to the primary data source

you're backups are not much good if they are destroyed or rendered inaccessible by a Critical Unplanned Failure

what are you going tell the client when ransomware hits and encrypts all the data on the ARRAY fat  lot of good raid 10 or raid 50 will do for that
what are you going to tell the client when they accidently delete 3 months of work and need it back (hey this is so and so from megacorpx I accidently deleted a project 3 weeks ago can you recover it)

what are you going to tell the client when a power supply goes Chernobyl and kills the raid controllers, sata backplane at 4 or more drives (I have seen this happen)

if RAID is your only backup nothing your FKd and likely will have some splainn todo

The rub is because RAID no matter the scale or complexity or redundancy its still a single point of failure
and the more you scale it up the worse it gets

your getting the backlash because effectively you are saying a single point of failure is an OK thing to have NO never ok Sometimes Unavoidable Yes: but never ever ever ever is it OK to intentionally implement one and tell the client 'this is fine'

if the data is critical to whatever operation then no raid is never a acceptable stand alone solution


----------



## newtekie1 (Jul 17, 2021)

lexluthermiester said:


> Do review...
> 
> 
> 
> ...


You literally posted confirming what I said. RAID 1, which uses mirroring, is the only RAID level that duplicates data.  The rest use parity, which *is not data duplication*.  And RAID 1 fails to meet the defintion of a backup because it doesn't protect against a data loss event.



lexluthermiester said:


> YOUR definition of backup, not everyone else's...
> 
> 
> 
> ...


Mine, and pretty much everyone else's. Even the wikipedia link you posted doesn't say RAID is a backup. It mentions RAID one time, and uses it in a scenario of "off-site RAID" where data is replication in real time off-site. Which isn't really even RAID they are just using the term for some reason.



lexluthermiester said:


> So am I and in two differing capacities.


I assume those capacities are "home user" and "gamer". Because I hope to god you aren't in charge of any company's IT systems or god forbid their data security.



lexluthermiester said:


> Do you see what you did there? You contradicted yourself.


No I didn't.



lexluthermiester said:


> Providing a layer of protection for data through *data duplication*, which is what most forms of RAID do, *is the exact same thing as making a backup*.


1.) RAID, with the exception of RAID1 is not using data duplication.
2.) Simply adding a layer of data protection does not meet the requirement to be a backup. You have to be able to recover from data loss on the volume for it to be a backup. If you can't recover the file the Bill over in accounting accidentally deleted, you don't have a backup. Period. End of discussion. *RAID IS NOT A BACKUP.*


lexluthermiester said:


> Making multiple copies of data for the purpose of protecting against data lost is literally making backups! This is not a difficult concept to understand. And yet, here we are...


RAID is not making multiple copies of the data, again except for arguably RAID1. Go look up what parity is, it isn't duplicating data.  If there were in fact multiple copies of the data in a RAID, the cost of the redundant storage would always be at least half the number of drives lost to redundancy, as for the data to truly be duplicated, it would have to exist twice in the RAID array.  So a 1MB file would need to take up at least 2MB of space to be considered duplicated.



lexluthermiester said:


> We could go on like this for days and those claiming RAID is not a form of backup will continue to argue their point and those who correctly understand the application and purpose of RAID will continue to point out how that perspective contradicts common knowledge and understanding. We're not going to succeed in convincing each other, so..


When you say "those who correctly understand the application and purpose of RAID", you mean you and only you. Because you're the only one arguing that RAID is a backup here.

Everyone else actually do correctly understand the application and purpose of RAID. It is not a backup, it shouldn't be considered as such, it is a layer to help protect data. But an anti-virus is a layer to protect data too, and we don't call that a backup.  All backups are a method of data protection, but not all methods of data protection are backups.  So...say it with me now...*RAID IS NOT A BACKUP.*


----------



## chrcoluk (Jul 17, 2021)

The old question has reared its head.

The only time RAID is a backup is when there is another copy of the data elsewhere, physically elsewhere.

But I suppose what we need to consider here is budgets.

In a world of no budget constraints, you have your data on a RAID, you then also back it up to a different location, and maybe even have another backup as well.  Typically my business stuff at the very least has a local backup, has snapshots, and is on redundant RAID, and on top of that is backed up at a different location.  In all usually 4-5 copies of the data minimum with it been on at least two different locations.

However when its my own data, and the person footing the bill for the storage is me, it works a bit different, there is a budget, there is limitations of storage, all sorts of things to consider.

BBU Raid card typically overkill for a personal user.
NAS cases making no financial sense.
Having 6+ drives typically out of many people's budget for a RAID solution.

I seen backblaze mentioned, and with their pricing model it should be seriously considered by home users, there is a saying I see on the internet "storage is cheap these days", no it isnt.

Consider this.

For a 4TB CMR drive, expect to pay circa £100.
Drives dont last forever so you have to replace the drive every X amount of years, how often depends how risk averse you are and luck, if you rarely power cycle and cool the drives, they have a higher chance of lasting longer, I currently have two 7 year old 3tb red's in my system and it is concerning me as the data on them only some of it is backed up.  Lets say you decide to replace every 4 years.  4TB capacity is then £25 per year, and that is with no redundancy or backups.
Add redundancy, lets say raid1, then thats £50 a year.
Add backups, now its £75 a year, boom you spending more than backblaze.  Plus its likely in this situation all your backups are at one location, so burglary, house fire etc. could lose it all.

First lets talk about the type of raid, I had this discussion on hardforum.
Its generally accepted now that Raid5 aka RaidZ1 is a bad idea.
So go Raid6 if you want that type of raid, or the alternative is Raid1.
Raid 1 has the lowest cost of entry, just 2 drives needed, can expand the ZFS pool with 2 drives at a time, new Raid1's added.
ZFS is probably the best software solution, it includes bitrot resistance with checksumming, scrub etc.
My plan is to buy a 4TB red, pair it with a 4TB red taken from my main PC, I have my starting Raid.
The next question at that point is are you happy with just redundancy which is effectively a hardware backup, but is "not" a data backup.
I still havent decided what I am doing, I think I will get a backblaze account, but the question will be if I just use that as backup and carry on using single drives, or combine it with a local raid mirror, probably the latter.

The value of local backups or local redundancy is you can recover quickly on hardware failure.  Its convenience.  The value of off site backups is you have gave yourself the best chance of keeping your data if a problem happens.  Even if its a slow recovery.

So if your budget allows for it I would go for a ZFS mirror combined with backblaze, otherwise just backblaze for backup, *I consider a offsite backup to single drive data superior to just one copy on raid*.

If you have no budget or living space concerns at all, then do all 3, Raid storage, local backup and backblaze backup.

My current situation.

OS is backed up to different physical drive in same system.
My modding work is backed up to different physical drive in same system.
My emails are backed up to different physical drive in same system.
Same with documents, game saves, pictures, and downloaded video clips, of youtube etc.

I currently have no backups at all for my recorded game footage, this I have some urgency on.
No backups of games, mostly not a big deal as can redownload, but maybe a problem for the modded games.

Most of my drives have ntfs shadow copies activated, so I can recover data from accidental edits etc., conveniently.

My plan is to change my ryzen rig to a home built NAS, it will use ZFS and mirrored storage.  This is far more cost efficient than buying a NAS unit.

At the very least the game footage videos will be put on there, I am also considering it to host all my other backups as well.  These backups will then have redundant storage and be in a different machine in a different room.

I then plan to upload data as well to backblaze for remote backups.  I do already auto mirror to the cloud my document, picture folders.  But this will be greatly expanded.  I have also considered using my own cloud service, as I have some servers in DC's with TB's of free storage, those might be an alternative option to backblaze, but either way there will be offsite backups of all the above mentioned data.

Losing data is painful, trust me on that one.


----------



## claes (Jul 18, 2021)

Poor @hat, just looking for some advice on RAID controllers, acknowledging that RAID isn’t a backup, and then their thread is hijacked with a debate about whether or not RAID is a backup after acknowledging it isn’t (OP’s plan is to use a single external drive to backup the RAID.)

@hat, here’s my suggestion about controllers, I hope it helps:



claes said:


> To get to your concern, most RAID AICs use the same couple of controllers and can often be flashed to other firmwares. You can often swap an array between cards if a) they use the same firmware (different models/controllers across LSI for example) or b) if they use the same controller and you flash to the appropriate firmware (Dell to LSI with same controller). The metadata is on the disks in the array, but, you know — always read the manual. I wouldn’t be surprised if the metadata is the same across vendors and they’re all just swappable, but I’ve never tried.
> 
> Finally, because the technology is so ubiquitous and there are so few vendors, you can often find a backup on eBay, or even new. The h700 I bought a decade ago is still the same price on eBay, and the 9750-4i I bought even longer ago for ~$250 new is now ~$125 new, ~$30 used.


Sorry for the wall of text, I should’ve been more concise.

As for the single troll debating everyone, 1) guys why do you bother he polices debates as absolute sovereign — it doesn’t matter if you actually work at a data center and deal with arrays all day, or if every legitimate DC on earth uses RAIDs and then backs them up; lex knows more than you about _everything_, has no humility, and will not tolerate your slights — and 2) outside of those wiki articles not saying RAID is a backup (good source), troll ought to consider — is splitting a drive into two volumes and duplicating the data across volumes a backup?

Singular mention of backup from the wiki:


> An array can be overwhelmed by catastrophic failure that exceeds its recovery capacity and the entire array is at risk of physical damage by fire, natural disaster, and human forces, however backups can be stored off site. An array is also vulnerable to controller failure because it is not always possible to migrate it to a new, different controller without data loss.[78]








						Backup - Wikipedia
					






					en.m.wikipedia.org
				




One mention of RAID:


> Backup media may be sent to an off-site vault to protect against a disaster or other site-specific problem. The vault can be as simple as a system administrator's home office or as sophisticated as a disaster-hardened, temperature-controlled, high-security bunker with facilities for backup media storage. A data replica can be off-site but also on-line (e.g., an off-site RAID mirror). Such a replica has fairly limited value as a backup.





			is raid a backup - Google Search
		


Have a good one : popcorn :


----------



## Ahhzz (Jul 18, 2021)

Yup. I think there have been several definitive posts on the definition "Is raid a backup", asked and answered. Any future discussion in this thread arguing the point will be removed, violent violators may be violated. 

Get back to the original topic, and let's give @hat our best opinion on his questions. thanks!


----------



## xrobwx71 (Jul 18, 2021)

lexluthermiester said:


> RAID enabled NAS are also solid options.


This is what I use as my offsite for work it has worked without issue for 8 years so far (since I moved from Lacie to Synology | 2 Lacies died on me). 

Sometimes I miss the tape days as far as reliability goes or maybe I was simply lucky back then.


----------



## freeagent (Jul 18, 2021)

If it is a home environment, what is the purpose of raid? Its not good for OS, not good for long term usage without a periodic backup. Then there is the expense.. Now for business use that gets a lot of hits, or there is constant high performance usage, I get it..  Outside of that I just don't see the need for it..


----------



## eidairaman1 (Jul 18, 2021)

To me raid is a faster backup method but is still vulnerable to drive failure, its good to implement more permenant methods though. im done sharing my thoughts on this.


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## newtekie1 (Jul 18, 2021)

freeagent said:


> If it is a home environment, what is the purpose of raid? Its not good for OS, not good for long term usage without a periodic backup. Then there is the expense.. Now for business use that gets a lot of hits, or there is constant high performance usage, I get it..  Outside of that I just don't see the need for it..


Space. It is useful in a home environment for space. I've got 12TB of media files on my home server, at the time it was cheaper to buy 3x6TB drives than a single 12TB.  Plus, it is better for long term storage than a single hard drive.  And of course I've had to upgrade over time as my media files grew. They now reside on a 24TB RAID array, which isn't even possible with a single drive.


----------



## freeagent (Jul 18, 2021)

Those numbers are much larger than I am used to dealing with  

I just played around a little.. and not even with a "good" controller..


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## Solaris17 (Jul 18, 2021)

I use backblaze B2 for my offsite, which isn’t what a lot of people use.

however I can’t say enough good things about them as a company, and while the consumer side doesn’t work for me they do offer unlimited storage for $60 a year.

which is a great deal if you look at carbonite, one drive, google drive etc.



			Pricing for Backblaze Online Backup
		


I’d do this rather than buying disks if this kind of storage works for you. @hat


----------



## hat (Jul 18, 2021)

Well this thread sure went for one hell of a ride!

Yeah, I recognize that RAID isn't a backup. I mentioned as much in my first post, when I went over issues such as UREs and controller deaths. That's why I'm thinking about an external hard drive... to back it up. To those of you suggesting Backblaze etc: I appreciate the suggestion, but I'm not a fan of the cloud. At least, not in this scenario. I think I should be covered with the external drive, barring some catastrophe that takes out both the RAID and the backup, in which case, I have bigger problems anyway...

I do have one specific question out of all this, however:


newtekie1 said:


> Uh, RAID1 and RAID10 definitely do have an issue of URE during a rebuild.


So, what exactly happens when you rebuild RAID1/10 and you run into a URE? From my understanding, if you get a URE when rebuilding a RAID5 array, your whole array is toast and none of the data is salvageable. I'd think RAID1/10 should just... skip over it and possibly that specific file becomes unusable?


----------



## newtekie1 (Jul 18, 2021)

hat said:


> So, what exactly happens when you rebuild RAID1/10 and you run into a URE? From my understanding, if you get a URE when rebuilding a RAID5 array, your whole array is toast and none of the data is salvageable. I'd think RAID1/10 should just... skip over it and possibly that specific file becomes unusable?


This is a hard question to answer as it isn't a black and white answer, even with RAID 5.

Worst case, you get an URE during a rebuild and the controller then kicks the drive that generated the URE out of the array. In which case, in RAID 1 or RAID 5 you're screwed with either.  This is one of the reasons RAID 6 is becoming popular, if a 2nd drive gets kicked out of the array during a rebuild, you are still ok.

However, a URE during a rebuilt can also just cause that block of data to be corrupt. If the controller doesn't kick the drive out of the array, then the rebuild just keeps on going but that block of data is corrupt.  RAID isn't file system aware.  It just deals in blocks of data, and a file can actually span several blocks and a block can have data in it from more than 1 file or a block can have no data in it at all. An URE doesn't always destroy the whole RAID5 array, it often just corrupts that block of data.

Adding nesting to get RAID 10 or 50 just reduces redundancy and should only be done when speed is a priority. Because if either of the RAID 1 or 5 arrays fails, kiss your data goodbye.


----------



## OneMoar (Jul 18, 2021)

Build a Freenas box
load it with drives and ram
./thread


----------



## Athlonite (Jul 18, 2021)

hat said:


> Have a read and see if my logic is sound... or point out any flaws...
> 
> I'm beginning to gather some data that's important-ish to me and I'd rather not lose it. So, rather than storing it on a single drive, I'd like to employ RAID. RAID5 seems like a good option, but I'm still rolling the dice on running into a URE if I ever have to rebuild the array should a drive fail. RAID1, or RAID10, doesn't have this issue, but all types of RAID do share one issue: a controller fault. Should the controller fail, you're still screwed, regardless of disk health, unless you can find the same controller again. This is data I'm going to keep around indefinitely, so I'm planning on _something_ to fail... else I wouldn't be considering RAID.
> 
> So, either way, something will fail and I'll be screwed. I guess this is why they say "RAID is not a backup!". In order to mitigate this, I would hazard a guess that a single external drive matching the size of my array should be an acceptable solution. Of course, this still doesn't work in the "somebody bombed my house" scenario, or in the astronomically unlikely event that both the RAID and the external totally fail at once, but I'm not thinking that extreme. This way, RAID5 should still be acceptable, even if I should run into a URE, as the data will be recoverable elsewhere. The loss of the RAID controller itself also isn't the end of the world.


Just how much DATA are you looking at needing to be backed up 
more than 8TB use a cloud solution they're quite cheap these days 
less than 8TB just buy and use and HDD in an external USB3.0 enclosure
as others have already said multiple times RAID is not a backup solution if you want to rely on for long term storage of important data


----------



## claes (Jul 18, 2021)

Friends, read the post — @hat is fully aware that RAID is not a backup, doesn’t want to use the cloud, has an idea of how much storage space they want, and has a backup plan. No need to beat a dead horse.


----------



## TheoneandonlyMrK (Jul 18, 2021)

You can't beat a good backup drive or two even.
But I've used raid 0 for years , transitioning and all sorts and initially there were snags, they're very robust and reliable these days and easy to use, ish


----------



## Aquinus (Jul 19, 2021)

TheLostSwede said:


> Just curious, how many hours did it take to rebuild after you lost a drive?


For RSTe, a couple hours-ish with my 1TB WD Blacks. Bigger drives are likely going to take longer. It depends on how much is going on while the rebuild is occurring, but I usually can use the machine while it's occurring. Any modern RAID implementation is pretty fast when it comes to RAID-5 though. It's not like a current gen CPU (or even my SB-e for that matter,) has to work very hard to XOR the parity bits to figure out what the missing blocks are supposed to be.


----------



## TheLostSwede (Jul 19, 2021)

Aquinus said:


> For RSTe, a couple hours-ish with my 1TB WD Blacks. Bigger drives are likely going to take longer. It depends on how much is going on while the rebuild is occurring, but I usually can use the machine while it's occurring. Any modern RAID implementation is pretty fast when it comes to RAID-5 though. It's not like a current gen CPU (or even my SB-e for that matter,) has to work very hard to XOR the parity bits to figure out what the missing blocks are supposed to be.


Tried to rebuild a RAID for test purposes when I worked at QNAP. That was with some kind of Atom CPU and took forever, as in a couple of days..


----------



## Jetster (Jul 19, 2021)

I'm really happy with TrueNas, formally FreeNas. You don't have to worry about a controller failing. ZFS and a RAID 6 so two drives would have to fail.
If a controller fails or a board you just replace it and you are bock up running.
Yes it is backed up somewhere else.  8 Tb of data


----------



## Aquinus (Jul 19, 2021)

TheLostSwede said:


> Tried to rebuild a RAID for test purposes when I worked at QNAP. That was with some kind of Atom CPU and took forever, as in a couple of days..


Yeah, it really depends on the implementation. RSTe has actually been one of the fastest implementations I've used. AMD's RAID is absolutely terrible (over 8 hours on at least on the 700 and 800 series chipsets, I actually eventually gave up and just used mdadm) and nVidia's when they used to produce nForce chipsets were okay (4-ish hours.) mdadm is almost on par with RSTe as well. Rebuild performance is decent on decent hardware and read performance on RAID 5/6 is exceptional. Write performance was a little lacking, but I think that has more to do with byte alignment of the blocks on the disk with the stripes of the RAID though.

All in all, I can't complain about RSTe or mdadm.


----------



## Operandi (Jul 19, 2021)

Jetster said:


> I'm really happy with TrueNas, formally FreeNas. You don't have to worry about a controller failing. ZFS and a RAID 6 so two drives would have to fail.
> If a controller fails or a board you just replace it and you are bock up running.
> Yes it is backed up somewhere else.  8 Tb of data


TrueNAS is pretty great but I'll point out that it is pretty picky about the hardware it likes to run on.  You can get it to work with a lot of controllers but its designed to be used with card/controller that works in pure HBA mode otherwise you run the risk of logical corruption.  Also by its nature every with ZFS every drive in the array needs to be identical which isn't really a downside of ZFS but there are other options out there that are more flexible.  Basically TrueNAS is designed to run on enterprise server hardware.

Another option to look at would be unRAID.  It works completely differently than TrueNAS and ZFS and allows you build the array with a mix and match of drives and build up the array over time.  Its also far more flexible on the hardware it will happily run on (pretty much anything).

You can also look at Xpenology which is basically a project that lets you run Synology on your own hardware.  I have no experience with it but people seem to like it.


----------



## MentalAcetylide (Jul 20, 2021)

There's just too much shit that can go wrong with RAIDs, much of which can be mitigated in a controlled commercial IT setting when compared to consumer desktops. It doesn't happen very often, but I do know that my system crashes or needs a hard/forced reboot a lot more frequently(due to software) than the one I use at work. I don't know about software RAID, but forced reboots & system crashes can be a big problem for hardware RAID. Quite frankly, if you don't need RAID, save yourself a ton of potential headaches and just do regular backup copies instead. While they can be beneficial depending on your needs, when things go wrong, it can be a pain in the ass; especially if you're not familiar with them.

Anyway, as long as you back everything up on a separate drive, you can run whatever RAID floats your boat without any worries of losing everything due to a system crash or hardware failure.


----------



## newtekie1 (Jul 20, 2021)

MentalAcetylide said:


> There's just too much shit that can go wrong with RAIDs, much of which can be mitigated in a controlled commercial IT setting when compared to consumer desktops. It doesn't happen very often, but I do know that my system crashes or needs a hard/forced reboot a lot more frequently(due to software) than the one I use at work. I don't know about software RAID, but forced reboots & system crashes can be a big problem for hardware RAID. Quite frankly, if you don't need RAID, save yourself a ton of potential headaches and just do regular backup copies instead. While they can be beneficial depending on your needs, when things go wrong, it can be a pain in the ass; especially if you're not familiar with them.


This just doesn't make any sense. RAID, with the exception of RAID 0,  makes data storage safer. Home use or not, data storage on a RAID 1/5/6 is safer than data storage on individual drives.

Hard reboots aren't a problem for RAID. You aren't going to lose all your data because you have to reboot the system, it doesn't work that way.  Worst case is if you have write-back cache enabled without a BBU. Then the data in the write cache will be lost. But that is just mitigated by using write-though cache instead, which is slower for writing but doesn't have the issues of data loss in the case of a unexpected shutdown.


----------



## Operandi (Jul 20, 2021)

newtekie1 said:


> This just doesn't make any sense. RAID, with the exception of RAID 0,  makes data storage safer. Home use or not, data storage on a RAID 1/5/6 is safer than data storage on individual drives.
> 
> Hard reboots aren't a problem for RAID. You aren't going to lose all your data because you have to reboot the system, it doesn't work that way.  Worst case is if you have write-back cache enabled without a BBU. Then the data in the write cache will be lost. But that is just mitigated by using write-though cache instead, which is slower for writing but doesn't have the issues of data loss in the case of a unexpected shutdown.


I think the point was any kind of RAID configuration is complex.  If all you need is another copy of the data a 10TB (or whatever capacity you need) USB hard drive is way less complex and less likely to fail than an array of 4+ drives not to mention the hardware managing it.  A NAS like Qnap or Synology or building your own TrueNAS or unRAID is resilient to downtime and can do all kinds of cool shit but there is no arguing its complex and has multiple points of failure.


----------



## dragontamer5788 (Jul 20, 2021)

Back when computers were slower, all of those calculations were too expensive to be conducted by the CPU. So you wanted a specialized ASIC to run the RAID5 checksum algorithms (aka: a RAID controller). But today, modern CPUs have so much spare compute power, you really don't want to be using a RAID controller anymore. In fact, many RAID systems on cheaper motherboards are just software RAID (a device driver that performs this RAID calculation, except it only works on a given motherboard that the device driver was made for). As such: RAID is just a bad idea: if the motherboard dies, there's no guarantee that a future motherboard knows how to read your RAID collection.

In contrast, a modern filesystem like ZFS (Linux/BSD) or ReFS (Windows enterprise storage spaces: "REsillient File System"), will be able to be rebuilt on a new motherboard automatically. If your "RAID" is all software anyway, might as well embrace the software-based methodology to the logical extreme and just use these features afforded by the operating system.

--------------

So when people today talk about "RAID5", they really mean running ZFS in 1-disk parity mode or Storage Spaces in 1-disk parity mode. I don't think people really mean buying a hardware RAID system anymore (ex: LSI MegaRAID or whatever). These software only solutions have been getting better and better (moreso on Linux, but ReFS / Windows Storage Spaces still has nice features worth talking about).

I recommend building a system with ZFS: be it Linux ZFS or BSD ZFS (Xigmanas is what I use) and really playing around with it. I also recommend 4-hard drives in striped+mirrored (aka: RAID10-like setup), which will only fail if 2x hard drives fail. striped+mirrored works efficiently in all software systems (Windows Storage Spaces and Linux), so its a good default. Linux's RAID5-like and RAID6-like software setups are known to be pretty efficient (Windows Storage Spaces not so much so). If you're going beyond 4-hard drives, working with Linux for 2x parity drives on say a 8-HDD setup is likely going to be less of a headache than 2x parity drives on Windows Storage Spaces. Windows works, but something about its algorithm is a good bit slower IIRC in this case.

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The main advantage of ZFS or ReFS is that Linux/Windows/BSD is more aware of the disks. In particular, the "ZFS Scrub" command will automatically scan all data and check for bitrot (and automatically correct any issues that come up). If you were using a hardware RAID system like LSI MegaRAID, Linux wouldn't necessarily know how to scrub / rebuild (it'd be part of the controller). There are also advanced software features like ZFS snapshots available.


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## Operandi (Jul 20, 2021)

Yeah hardware RAID isn't really a thing anymore.  I'm sure Qnap or Synology are doing it in their software.

If the OP (or anyone else) builds a NAS there are tons of LSI controller cards out there and you certainly can use them to build an array what you really want is one that is configured to work like pure HBA that just presents the disks to the system and let software (TrueNAS, unRAID) handle all the parity and rebuilding stuff.


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## dragontamer5788 (Jul 20, 2021)

Operandi said:


> Yeah hardware RAID isn't really a thing anymore.  I'm sure Qnap or Synology are doing it in their software.
> 
> If the OP (or anyone else) builds a NAS there are tons of LSI controller cards out there and you certainly can use them to build an array what you really want is one that is configured to work like pure HBA that just presents the disks to the system and let software (TrueNAS, unRAID) handle all the parity and rebuilding stuff.



And dedup, and NVMe cache, and scrubbing, and snapshots, and...

Seriously. Software solutions these days have so many features that hardware RAID is no longer a contender IMO. Especially in this day and age where we can just buy an 4-core/8-thread chip under $200 (Ex: AMD Ryzen 3 3300X). Sure its Zen2 instead of Zen3, but you probably don't need a Zen3 to run just a NAS workload.

EDIT: So to be clear: I'm recommending a 2nd computer to serve as a NAS. If you want the NAS-storage to be used on your main computer, carve up a bit of the NAS volume into an iSCSI and have your main desktop connect to the NAS remotely. If you don't like the idea of running your hard-drives over a network (despite 1Gbps ethernet supporting ~100MB/s transfer speeds), try Windows Storage Spaces (which would keep the entire solution local to your Desktop).


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## ShiBDiB (Jul 21, 2021)

It depends what you're storing (which I didn't see stated anywhere). Unless it's something super sensitive, just use a legitimate cloud provider as your backup. 

As can be seen by this cluster of a thread, RAID is not the answer for a no bs backup solution.


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## Hypnotized621 (Jul 22, 2021)

Idk why people keep going on about RAID0 and losing everything because of a HDD or SSD failure. I mean, if you only had one HDD or SSD and that fails the same thing happens.


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## Ahhzz (Jul 22, 2021)

Hypnotized621 said:


> Idk why people keep going on about RAID0 and losing everything because of a HDD or SSD failure. I mean, if you only had one HDD or SSD and that fails the same thing happens.


No one in here _is_ going on about a Raid0 and losing everything. Everyone here understands what Raid0 is, and its limitations, and purpose.


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## ThrashZone (Jul 22, 2021)

Hi,
I personally keep things simple as possible and backup wise works for me
Only raid I know of comes in a can to kill bugs


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## newtekie1 (Jul 22, 2021)

Operandi said:


> I think the point was any kind of RAID configuration is complex.  If all you need is another copy of the data a 10TB (or whatever capacity you need) USB hard drive is way less complex and less likely to fail than an array of 4+ drives not to mention the hardware managing it.  A NAS like Qnap or Synology or building your own TrueNAS or unRAID is resilient to downtime and can do all kinds of cool shit but there is no arguing its complex and has multiple points of failure.


This is exactly why were are saying RAID isn't a backup. If you just need a backup of your data, yes get a 2nd drive and back your data up to that drive.  RAID serves a different purpose.



ShiBDiB said:


> It depends what you're storing (which I didn't see stated anywhere). Unless it's something super sensitive, just use a legitimate cloud provider as your backup.
> 
> As can be seen by this cluster of a thread, RAID is not the answer for a no bs backup solution.


Cloud solutions aren't always feasible. I mean, I have 20TB of data that I want to have instant access to, I also have a 1TB per month data cap. Both situations prohibit me from just storing everything in cloud.


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## Athlonite (Jul 23, 2021)

newtekie1 said:


> Cloud solutions aren't always feasible. I mean, I have 20TB of data that I want to have instant access to, I also have a 1TB per month data cap. Both situations prohibit me from just storing everything in cloud.


That's a pretty big porn collection lol


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## OneMoar (Jul 23, 2021)

Athlonite said:


> That's a pretty big porn collection lol


Its not all porn some of it is furry hentai


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## newtekie1 (Jul 23, 2021)

Athlonite said:


> That's a pretty big porn collection lol


Don't be jealous, only half of it is porn. The rest is the non-nude pictures of your mom.


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