Re: PostgreSQL on Solaris 8 and ufs

Brandon Metcalf wrote:

>We've recently moved our pgsql installation and DBs to a Solaris 8
>machine with striped and mirrored ufs filesystem that houses the DB
>data. We are now seeing terrible performance and the bottleneck is no
>doubt disk I/O.
>
>We've tried modifying a tunables related to ufs, but it doesn't seem
>to be helping.
>
>Is there anything we should be looking at that is specifically related
>to ufs filesystems on Solaris 8 or possibly something in general that
>would improve performance?
>
>
Well, Solaris 8 is a bit old now, so I don't remember all the details.
But, if memory servers, Solaris 8 still has some "high water" and "lo
water" tunables related to the amount of IO can be outstanding to a
single file.

Try setting
set ufs:ufs_WRITES=0
in /etc/system and rebooting, which basically says "any amount of disk
IO can be outstanding". There's a tunables doc on docs.sun.com that
explains this option.

Also, logging UFS might help with some of the metadata requirements of
UFS as well. So, use "mount -o logging" or add the relevant entry in
/etc/vfstab.

Of course, the best thing is Solaris 9 or 10, which would be much better
for this sort of thing.

Hope this helps.

-- Alan