# RAID Stripe size



## khanman125 (Jun 23, 2015)

I'm in the process of upgrading my computer with 2 new drives in RAID 0. 2x WD 1TB SATA 6GBs. What is the optimal stripe size?


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## INSTG8R (Jun 23, 2015)

LOL I have that exact same setup I went with 128 but hey if someone has a better suggestion I just formatted so I have no reason not to change it.


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## khanman125 (Jun 23, 2015)

Haha, does 128 give better performance?


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## Disparia (Jun 23, 2015)

Generally the default is the best value for all-around performance. For Intel RAID-0 that's 128KB for most chipsets, if not all of them. Newer Adaptec and LSI controllers have values of 256KB or greater as they're designed that way. So it's not so much that any specific value is better than another as it depends on the controller to a large extent. Deviation from the default is usually due to the array being used for a very specific purpose.


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## Bill_Bright (Jun 23, 2015)

Why do you want RAID0? If looking to optimize performance (and I see no other reason for RAID0) then if me, I sure would skip RAID0 with 2 HDs and spend that money on 1 SSD then blow the socks of any HD configuration you could come up with.


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## newtekie1 (Jun 23, 2015)

AFAIK, 128KB is better for random access and 64KB is better for sustained file transfers.  

I believe 128KB is generally considered the best for general use.


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## Steevo (Jun 23, 2015)

Storage capacity, speed improvements.


The only fault of RAID 0 beyond its intolerance to failure is the seek times.


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## Loosenut (Jun 23, 2015)

I used to run RAID0 until I got an SSD. Much faster. Keep my OS on SSD, games, apps. and storage on the other drives.


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## CrAsHnBuRnXp (Jun 23, 2015)

I think this post in my RAID Arrays explained post may answer your question.

http://www.techpowerup.com/forums/threads/raid-arrays-explained.43572/page-2#post-1058067


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## Disparia (Jun 23, 2015)

CrAsHnBuRnXp said:


> I think this post in my RAID Arrays explained post may answer your question.
> 
> http://www.techpowerup.com/forums/threads/raid-arrays-explained.43572/page-2#post-1058067



Except that's incorrect information as I stated 3 posts under it. Stripe size is being confused with cluster.


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## CrAsHnBuRnXp (Jun 23, 2015)

Jizzler said:


> Except that's incorrect information as I stated 3 posts under it. Stripe size is being confused with cluster.


Then please provide here the information differentiating the two and provide examples as to better help the OP with his issue.


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## khanman125 (Jun 23, 2015)

I have a Intel 120gb ssd for the OS, and want to use the 2 drives in RAID for storage.


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## Bill_Bright (Jun 23, 2015)

Steevo said:


> The only fault of RAID 0 beyond its intolerance to failure is the seek times.


I think it is beyond intolerance.

With 2 drives in RAID 1 mirror, you lose 1 drive, you've lost zero data.
If you lose the RAID controller with RAID 1, you still have all your data.
With 2 separate drives, you lose 1 drive, you only lose the data on the failed drive.
With 2 drives in RAID 0 striped, you lose 1 drive, you've lost everything!
And if you lose the RAID controller RAID 2, you may lose everything!

Do you really need that kind of storage capacity in a striped array?

Years ago, striped RAID was the way to go for performance. But those days are gone. There are better options that give you speed, and fault tolerance (and capacity too). Including SSDs or SSD + HD (plus a backup plan).


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## Aquinus (Jun 23, 2015)

CrAsHnBuRnXp said:


> I think this post in my RAID Arrays explained post may answer your question.
> 
> http://www.techpowerup.com/forums/threads/raid-arrays-explained.43572/page-2#post-1058067



Stripe size is the size of each chunk written to each physical drive. So if you have your logical RAID disk with 128k stripes, you will bop between the two disks that many times. If you have a file system with 64k blocks, you will write two block before bopping to the other disk. You don't "save space" from using smaller stripes. What he is confusing is those two things because if you write a 2k file with 64k blocks, you will eat up 64k, but the next 2k file you write will still be on the same stripe.

I think the only time when smaller stripes matter are with SSDs. Smaller stripes mean less superfuous writes to free memory because of the size of the stripes. It also means fewer delete cycles on cells that never had values stored to them. 4k blocks also seem to do great things for latency but bad things for bandwidth.

It seems that smaller stripes seem to benefit latency where bigger stripes seem to benefit bandwidth. Whether you're using SSDs or HDDs will determine the benefit from going either way. The kind of data you're storing will also impact performance based on your stripe size and disk type.


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## Steevo (Jun 23, 2015)

Bill_Bright said:


> I think it is beyond intolerance.
> 
> With 2 drives in RAID 1 mirror, you lose 1 drive, you've lost zero data.
> If you lose the RAID controller with RAID 1, you still have all your data.
> ...



Thats a lot of typing to say the same thing I said.

Also, RAID 0 still works well on HDD's, I have two 3TB drives on a RAID card that run all my games, pictures, movies, music, and much else. 200MBps read and write speed and yes I have backups of my pictures, music, and videos, games are on steam and can be redownloaded, but they are also backed up onto a separate HDD.


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## khanman125 (Jun 23, 2015)

This leads to my next question, can you have multiple arrays on one controller?


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## Aquinus (Jun 23, 2015)

khanman125 said:


> This leads to my next question, can you have multiple arrays on one controller?


Yes. In fact both my RAID-0 with SSDs and RAID-5 with HDDs are both running off the X79 PCH.


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## Bill_Bright (Jun 23, 2015)

Depends on the controller but yeah. And for sure, many use mirror and striped on the same array for both speed and redundancy. But obviously, that takes more drives, thus costs more.


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## Aquinus (Jun 23, 2015)

Steevo said:


> View attachment 65992
> 
> Thats a lot of typing to say the same thing I said.
> 
> Also, RAID 0 still works well on HDD's, I have two 3TB drives on a RAID card that run all my games, pictures, movies, music, and much else. 200MBps read and write speed and yes I have backups of my pictures, music, and videos, games are on steam and can be redownloaded, but they are also backed up onto a separate HDD.


RAID-5 is seriously underestimated. Consider this performance while still maintaining redundancy. If you like 200MB/s, you'll love 300MB/s and redundancy. 




Plus, four 1TB cost slightly less than two 3TB drives. If you have the RAID-5 capability it's the same capacity, added bandwidth, and less cost (if you consider 1TB WD Black versus 3TB WD Black.) Sometimes it's worth it to use smaller drives when using RAID but, once again, you need the controller and SATA ports to drive everything you want to use.

I personally love the RAID-0 and RAID-5 combo if you want to throw all of your eggs in one basket.


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## Steevo (Jun 23, 2015)

I love me a RAID5, but the card...... it only has 4 native ports (can use port expanders), and I was running my two SSD's in RAID0 before I killed one, and two HDD's in a separate array, and currently 6TB of primary storage is enough for me.


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## Bill_Bright (Jun 23, 2015)

One of the problem with redundant arrays is the cost initially to set them up because of the extra drives needed. And you really need to buy any extra drives you MIGHT need in the years following at the same time and put them on the shelf to ensure compatibility when the time comes.

When I ran mirrored RAID in my main system years ago for my repair shop, I bought 3 identical drives, then every month, swapped in the spare and stored the removed drive in the safe deposit box at my bank. This way I always had a fairly recent off-site backup. Now I just copy to my old repurposed XP storage server in the basement and hope my house does not burn down.


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## Steevo (Jun 23, 2015)

With offsite storage allowed by so many companies you can make online backups for free of most of your really important stuff. Google Drive, MS OneDrive... http://www.pcworld.com/article/2037131/supersize-your-free-cloud-storage-to-100gb-or-more.html


I get a lot I have never even used just from my past participation in MS programs and from being a partner for so long. They are still giving "Cloud" time and storage away for free too.


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## khanman125 (Jun 23, 2015)

I could care less about redundancy in my case, all my important files I back up onto an external drive and keep somewhere else. I'm mainly just looking for preformance.


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## Bill_Bright (Jun 23, 2015)

Well, I trust "the cloud" would not lose my backups - but I still don't trust "the cloud" to keep my data secure from badguys. So I don't put anything important out there that contains any of my personal data, or that of my clients. There are just too many well funded organizations, often hostile government backed (China, N. Korea, Iran, etc.) actively trying to hack into those cloud services. And not just actively trying, but succeeding too.  So nope! No cloud storage for anything I don't want shared, stolen or compromised.


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## newtekie1 (Jun 23, 2015)

Bill_Bright said:


> And you really need to buy any extra drives you MIGHT need in the years following at the same time and put them on the shelf to ensure compatibility when the time comes.



That is definitely not true.  While it is ideal to use identical drives, it is certainly not required on any modern RAID controller.  And with most modern controllers also supporting OCE and ORLM you don't even have to loose access to the array while you are adding the extra drive.



Bill_Bright said:


> There are just too many well funded organizations, often hostile government backed (China, N. Korea, Iran, etc.) actively trying to hack into those cloud services. And not just actively trying, but succeeding too.  So nope! No cloud storage for anything I don't want shared, stolen or compromised.



They can hack into my cloud storage all they want, good luck to them cracking the 256-bit encryption on all of the files that are encrypted on my local machine before they are uploaded to the cloud.


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## Steevo (Jun 23, 2015)

Data density has as much if not more to do with performance from mechanical HDD's than anything. But if pure performance is what you want get 2 4TB drives, short stroke them and put them in they array at half capacity.


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## Bill_Bright (Jun 23, 2015)

newtekie1 said:


> That is definitely not true. While it is ideal to use identical drives, it is certainly not required on any modern RAID controller.


I agree if you get a separate dedicated controller (or at least a upper end motherboard with decent controller). And for sure, modern controllers are much more accommodating. But I have still seen recent problems of compatibility.

That said, by "recent", I mean the problems I encountered surfaced recently. The server, drives and controllers are all from 5 years ago. So with 2015 controllers and drive failures in 2020, compatibility hopefully will not be an issue.


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## xvi (Jun 23, 2015)

Bill_Bright said:


> No cloud storage for anything I don't want shared, stolen or compromised.


Sounds like you need a "personal cloud". 
(I hate that term.)


Aquinus said:


> RAID-5 is seriously underestimated. Consider this performance while still maintaining redundancy. If you like 200MB/s, you'll love 300MB/s and redundancy.


I think people's distaste for RAID5 was back when controllers couldn't keep up calculating parity data (or at least I _think_ that was a thing. I was young then, never got to play with it). On top of that, I don't think older controllers liked reading from the parity drive to give full read performance. These days though, n-1 write performance, n read performance, nice fault tolerance, very widely supported.. I've always thought RAID5 is the way to go for home use.


Steevo said:


> Data density has as much if not more to do with performance from mechanical HDD's than anything. But if pure performance is what you want get 2 4TB drives, short stroke them and put them in they array at half capacity.


The idea was better seek times and to keep files off the slower end of the drive, right? Never heard how much that improved things.


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## Steevo (Jun 23, 2015)

xvi said:


> Sounds like you need a "personal cloud".
> (I hate that term.)
> 
> I think people's distaste for RAID5 was back when controllers couldn't keep up calculating parity data (or at least I _think_ that was a thing. I was young then, never got to play with it). On top of that, I don't think older controllers liked reading from the parity drive to give full read performance. These days though, n-1 write performance, n read performance, nice fault tolerance, very widely supported.. I've always thought RAID5 is the way to go for home use.
> ...




Yeah it used to be a huge thing for RAID 5 when CPU's handled the overhead through drivers, and it cost 25% of a systems performance (1Ghz CPU single core) to run a decent array, but with modern controllers the CPU use and or onboard hardware has eliminated this problem. 


Instead of 50% degradation of performance you may only have 15%, and cut seek times by a third.


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