Re: [PERFORM] PostgreSQL on Solaris 8 and ufs

[Alan Stange]

Brandon Metcalf wrote:

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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
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