[CentOS] XFS on a 25 TB device

Wed Sep 29 15:27:27 UTC 2010
Peter Kjellstrom <cap at nsc.liu.se>

On Wednesday 29 September 2010, Boris Epstein wrote:
> Hello all,
>
> I have just configured a 64-bit CentOS 5.5 machine to support an XFS
> filesystem as specified in the subject line. The filesystem will be used to
> store an extremely large number of files (in the tens of millions). Due to
> its extremely large size, would there be any non-standard XFS
> build/configuration options I should consider?

I have created and tested filesystems larger than 25T using xfs on CentOS-5
(64-bit). I did not use any non-standard options. Do not attempt this on a 
32-bit box.

However, given the size of the device I assume that this is a raid of some 
sort. You'll want to make sure to run mkfs.xfs with the proper stripe 
parameters to get the alignment right. Also, you may want to make sure your 
LVM or partition table is properly aligned.

Even with the above done right you may get worse performance than expected 
since "lots of small files" typically reads like "terrible performance".

Finally I'd suggest you fill the filesystem and read it back (verifying what 
you wrote). This is, imho, a reasonable level of paranoia.

/Peter

> Thanks.
>
> Boris.
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