[CentOS] ext4 or XFS

Tue Jan 11 21:17:12 UTC 2011
James A. Peltier <jpeltier at sfu.ca>

----- Original Message -----
| On Jan 11, 2011, at 10:59 AM, Joshua Baker-LePain wrote:
| 
| > On Tue, 11 Jan 2011 at 1:49pm, Digimer wrote
| >
| >> On 01/11/2011 01:47 PM, aurfalien at gmail.com wrote:
| >>> Hi all,
| >>>
| >>> I've a 30TB hardware based RAID array.
| >>>
| >>> Wondering what you all thought of using ext4 over XFS.
| >>>
| >>> I've been a big XFS fan for years as I'm an Irix transplant but
| >>> would
| >>> like your opinions.
| >>>
| >>> This 30TB drive will be an NFS exported asset for my users housing
| >>> home dirs and other frequently accessed files.
| >>>
| >>
| >> You will need XFS for a single partition that large. You won't be
| >> able
| >> to make such a large ext4 partition, I don't think.
| >
| > This is correct. While ext4 theoretically supports volumes (much)
| > larger
| > than 16TB, the developers don't think it's production ready yet and
| > the
| > userspace tools don't support it yet.
| >
| > So, short answer -- XFS is the only way to go.
| >
| 
| My RAID has a strip size of of 32KB and a block size of 512bytes.
| 
| I've usually just done blind XFS formats but would like to tune it for
| smaller files. Of course big/small is relative but in my env, small
| means sub 300MB or so.
| 
| What would your XFS tuning params be for such an env?
| 
| - aurf
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Your sw and su options should match the number of *usable* data disk and your stripe size to best optimize performance.

Do *not* create a volume this large unless you have a lot of memory.  If you ever need to run an xfs_check on the volume you could be looking at 10s of GB of memory.  I just ran an xfs_check on an 11TB volume used by our medical imaging lab and the xfs_check/xfs_db process grew to around 32GB of CentOS 5.5 64-bit.

-- 
James A. Peltier
Research Computing Group
Simon Fraser University - Burnaby Campus
Phone   : 778-782-6573
Fax     : 778-782-3045
E-Mail  : jpeltier at sfu.ca
Website : http://www.sfu.ca/itservices
          http://blogs.sfu.ca/people/jpeltier