Re: XFS performance

[Stephen Lord <lord@sgi.com>]

Alexey Tsyban wrote:

>
>Hi,
>
>I just have tested performance of xfs and ext3 on my new Dell PowerEdge 1550
>RERC3/DLC RAID with 3 36Gb disks in RAID5, Dual PIII 1000. Running linux
>slackware 8.0 glibc 2.2.5 with linux 2.4.17 from cvs tree.
>Mkfs options -l size=8192b, partition size 30Gb
>mount options logbufs=4,osyncisdsync
>
Numbers removed

>
>As I see ext3 is match faster. Why??
>May be I should use another mount options or mkfs options to have better
>performance?
>

With software raid5, xfs does not like having its log in the middle of 
the drive,
the raid5 code and xfs log writes do not interact well, but that should 
not be an issue
here.

Some of those numbers my puny little scsi drive beats quite nicely, and
on others I ran out of cpu power (2 x 450MHz PIII with 128M).

You say you have 3 drives configured as raid5 - how? What is the stripe
unit? I do not know for certain, but 3 seems like a funny number. Can
you run xfs_growfs -n /xxx where /xxx is the mount point? It is possible
to teach xfs about stripe units of raid devices, but getting it right can be
tricky.

Are you running ext3 with data journalling or without?

Steve