# Seeking opinions on server builds.



## SAlexson (Oct 22, 2007)

I run a couple of small servers at home for personal use. These servers run firewall, DNS, mail, several small web sites, ssh, mysql, and ftp services. The current operating system is SuSE 10. I am in the process of upgrading the hardware of these servers (currently they are PII 450 Mhz with 384 MB RAM).

The new servers will be:
- Motherboard: ASUS M2A-VM AM2 AMD 690G Micro ATX AMD Motherboard
- Processor: AMD Athlon 64 X2 4200+ Windsor 2.2GHz Socket AM2 65W Processor
- Memory: 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Memory (will be upgraded to 4GB in the near future)
- Hard Drive: 2 x Seagate Barracuda 250GB 7200 RPM 16MB Cache SATA 3.0Gb/s Hard Drive (RAID 1)
- Network: 2 x Intel 10/100/1000Mbps PCI PRO/1000 Network Adapter 

Servers will be running:
- Apache Web Server
- Apache Directory
- OpenSSH
- MySQL
- VSFTP
- Courier IMAP
- Postfix
- Amavis
- Clam AV
- SpamAssassin
- Firewall services

These servers will have no desktop use. X-Windows will be running, but only for remote administration of services via XDMCP.

So here are my questions. Any CONSTRUCTIVE opinions would be greatly appreciated.

1. I am planning on installing CentOS 5 as the base OS for these new servers. With the processor I chose, would it be beneficial to run the 64-bit version of the OS? Would there be any potential problems?

2. With only 2 hard drives, would there be much value added to data integrity/security with them configured in a RAID 1 array? More to the point, if one fails, should I be able to replace it and have it rebuilt by the array? Does it matter if it is the "master" drive in the array? Do you think that performance overhead of the RAID 1 array will outway the benefits? Would a different RAID configuration be more beneficial. Data redundancy is more critical to me than available space.

3. What is the standard for the size of the swap partition. Way back when, I remember the rule of thumb being: swap partition = 1.5 x physical ram size. Does this still hold true? That would put me at a 3 GB swap partition (6 GB if I plan for the upgrade to 4 GB RAM). Also, has anyone experimented with performance benefits of putting the swap partition at different locations on the drive (i.e beginning of drive, middle, or end)?

4. I have a 500GB NAS that I will be using to store system backups. Does anyone know of any software or methods to take effective backups that are stored on a NAS as opposed to a tape drive? One of my friends mentioned using rdiff. Any other thoughts, or comments supporting rdiff?

Thanks in advance for any and all CONSTRUCTIVE opinions. I am looking forward to building these servers with CentOS 5. I have installed it in a test environment, but I can't wait to see it run on this hardware!


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## Easy Rhino (Oct 22, 2007)

good luck with those builds. i have never used any linux OS on a server, just freebsd.


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## Deleted member 3 (Oct 22, 2007)

How many users are you planning on serving? For a home server those specs seem a bit overkill. Specially when you consider the listed services.

As for the value of RAID1, it is a mirror, ie a whole drive can fail and the system will keep running. Performance wise there is no overhead when using a decent controller, in fact read performance will go up. RAID1 is the best solution for data safety, if you want some extra performance and space you could go for RAID5 which uses 1 disk for parity so a single disk in the array could fail.


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## Ben Clarke (Oct 22, 2007)

Damn, Dan beat me. Listen to what he said, he runs one of the ghreatest websites of all: http://danthebanjoman.nl/


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## SAlexson (Oct 22, 2007)

DanTheBanjoman said:


> How many users are you planning on serving? For a home server those specs seem a bit overkill. Specially when you consider the listed services.
> 
> As for the value of RAID1, it is a mirror, ie a whole drive can fail and the system will keep running. Performance wise there is no overhead when using a decent controller, in fact read performance will go up. RAID1 is the best solution for data safety, if you want some extra performance and space you could go for RAID5 which uses 1 disk for parity so a single disk in the array could fail.



Oh, believe me, I know it is overkill, but it is about the biggest bang for the buck as far as the hardware goes. mail-wise maybe a couple dozen users. Website-wise could be on the order of a few 100 users. Not much, but again, biggest bang for the buck. Not worried about overhead from concurrent users.

So, for RAID1...(for some reason, I can't fully wrap my mind around this)
In a 2 disk array, either disk can fail and be rebuilt from the healthy disk, correct? I did read that you can get a read performance boost if the controller uses both disks to access data. So, basically my biggest concern is data safety. As long as either disk can fail and be rebuilt from the remaining, healthy disk, I will be content.

Thanks for the feedback.


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## Deleted member 3 (Oct 22, 2007)

What RAID1 basically does is write identical adta to both disks, when 1 disk fails it can just copy everything over. However, RAID is not a backup as many people believe. If you get a virus or manage to delete important files data is lost. Keeping files backed up is not a bad idea when they're important.


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## SAlexson (Oct 22, 2007)

DanTheBanjoman said:


> What RAID1 basically does is write identical adta to both disks, when 1 disk fails it can just copy everything over. However, RAID is not a backup as many people believe. If you get a virus or manage to delete important files data is lost. Keeping files backed up is not a bad idea when they're important.




Well, the RAID1 is only to prevent against complete data loss in the event of a hardware failure. I do have a 500GB NAS that will be used for true backup purposes.


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## Deleted member 3 (Oct 22, 2007)

SAlexson said:


> Well, the RAID1 is only to prevent against complete data loss in the event of a hardware failure. I do have a 500GB NAS that will be used for true backup purposes.



As long as you are aware that RAID isn't a reason not to make backups you're fine.


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## SAlexson (Oct 22, 2007)

DanTheBanjoman said:


> As long as you are aware that RAID isn't a reason not to make backups you're fine.



Well, then I am set for the RAID question I had.  Thanks for clarifying that part.


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## lemonadesoda (Oct 22, 2007)

Yes, thats a VERY important point. RAID is only for hardware failure, and is not an effective backup solution. You can use the NAS. I would recommend having separate partitions to "grandfather" your backups if the data is really critical and there is a possibility of one of your users not noticing a mistake until AFTER a new backup was made.

1./ I have used Handybackup for NAS backups http://www.handybackup.net/ (Application runs no PC and transfer TO the NAS). You can do a FULL backup followed by incremental backups. You can schedule backups as a service. You can run it from your main PC and it will not create too much overhead, so you can use your PC will it works. HOWEVER, it is not a very clever solution if you run your PC, but want to back up data from SERVER A to the NAS.  Why? Because it becomes network traffic heavy... copying the data from SERVER A to the PC then to the NAS.  Unfortunately, I've not seen a consumer level NAS that has good built in backup software.  So maybe you need to install copies of your backup software directly onto each SERVER so they back themselves up on a regular schedule.

2./ I'm not recommending Handybackup... its just an example that works ok for me.  There are many other products out there. Best to google and see what you find.  I'm sure there is freeware too. If you find something good, report back!

3./ Learned through experience, I find that for a small scale backup requirement, like yours, the SIMPLEST solution as well as the FASTEST to execute, is just to buy a second HDD for the servers.  Since you can buy a 500GB drive these days for $80/EUR80, they are quite cheap. A backup task is therefore done on internal ATA/SATA and is very very much quicker than even gigabit ethernet and doesnt hog any external resources.

4./ I bought my NAS for fileserving.  But since trying to implement backup solutions that are QUICK and dont require manual intervention, I now regret getting the NAS. Better to opt for a  small PC running as a fileserver, with its own built in backup service making frequent copies to a second internal HDD.  This is what i would implement NOW if I was setting up my network infrastructure again.

5./ Sorry, I have no tips for linux.


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