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I'll be running ubuntu server on a 3 disks server (450 GB each) and 16 GBs of RAM.

My target at the moment isn't configuting MySQL itself, but what could be the best RAID configuration for my case here (Top priority is for system availability\data-protection and then comes performance, the disks are pretty fast anyway).

I've been reading for a while about partitioning and I'm thinking about doing the following:

  • I'll have different partitions for /boot, /, swap, /home and /db (holding all mysql files). This schema is for no particular reason other than separating each aspect of the OS from the other so no partition would steal space from other critical partitions.

But I have no idea what file system should I use for each partition ? Is it ok to have different file systems for each partition ? Are their recommended ones for /boot, / ? For MySQL, I'm not sure yet, it's debates everywhere ! I only need something stable and easy to handle. I'm pretty sure these disks speed will do just fine for our needs and the partition size will hardly be an issue

EDIT: Will use RAID 0 for swap partitions, RAID 1 for the /boot partition and RAID 10 for the rest. I only have 3 disks and my main concern is the reading throughput (database reports), not the writing throughput, and of course system availability.Use RAID 5 because I only have 3 disks and my main concern is the reading throughput (reports), not the writing throughput.

But I'm not sure how to configure a RAID array. I've followed ubuntu's server partitioning guide and I was confused by only having 2 partitions, one for swap and one for /. While the one for swap is bootable and used as "physical volume for RAID", why is that ? And what does "physical volume for RAID" mean ?

EDIT: What would be a recommended swap space if the RAM is 16 GB ? I say 4 GB, just to reduce the I/O blocking. What do you think ?

Any suggestions are mostly welcomed.

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RAID5 is no longer a good choice... since about 10 years. Neither for speed, nor for security. Use 2 disks in mirror and you'll get a better throughput (except for a straight continuous read, nearly never seen in real life). –  Gregory MOUSSAT Jul 29 '12 at 17:15
    
@GregoryMOUSSAT, Thanks. But I still need the system available in case of a disk failure. Is their a better way to achieve that using 3 disks or may be 2 ?! –  Muhammad Gelbana Jul 29 '12 at 17:19
    
There is also raid 10 on 3 disks...but I don't know if it's available on hw raid controllers. –  Jure1873 Jul 29 '12 at 18:41
    
@Jure1873, with one as a spare ? –  Muhammad Gelbana Jul 29 '12 at 19:09
    
No, Raid 10 means raid 1 + 0 = mirroring + striping. With linux sw raid you can also create raid 10 with 3 disks. See Raid10,f2 on 3 disks: en.wikipedia.org/wiki/Non-standard_RAID_levels#Linux_MD_RAID_10 –  Jure1873 Jul 29 '12 at 20:44

1 Answer 1

up vote 3 down vote accepted

If you have an option of going the a fourth disk, four disks in a RAID 1+0 will be an all-around better solution than the RAID 5 arrangement you're speaking of.

See our canonical answer about this here.

Other considerations are your hardware RAID controller... Will you have a solution with read and write caching (battery or flash-backed cached solutions will help write-speed)? Filesystems make a bit of a difference as well. XFS is well-regarded in this space, but it requires some tuning to work well.

As far as swap space, I rarely allocate more than 8GB of swap. Maybe 12GB or 16GB in certain cases...

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If the RAID array was my decision I would've gone for RAID 10 but it isn't and I still don't know the full specs of the disks yet. So far I'm trying to decide whether to use XFS or JFS for MySQL's partition. –  Muhammad Gelbana Jul 29 '12 at 17:41
    
The disks are 450GB enterprise SAS disks in either 10k or 15k RPM. That's fairly clear. I don't know that JFS is as widely used as XFS. But either way, the RAID 5 is a bit of an issue. –  ewwhite Jul 29 '12 at 17:44
    
JFS is the worst i've tested when faced with hardware failure (serverfault.com/a/206837/6125). Go with Ext3/4 if you don't need more than 8TB, XFS if you do. –  Javier Jul 30 '12 at 2:46

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