On Wed, Dec 14, 2005 at 08:28:56PM +1300, Mark Kirkwood wrote:
> Another interesting thing to try is rebuilding the database ufs
> filesystem(s) with 32K blocks and 4K frags (as opposed to 8K/1K or
> 16K/2K - can't recall the default on 4.x). I found this to give a factor
> of 2 speedup on random disk access (specifically queries doing indexed
> joins).
Even if you're doing a lot of random IO? I would think that random IO
would perform better if you use smaller (8K) blocks, since there's less
data being read in and then just thrown away that way.
> Is it mainly your 2 disk machines that are IOPS bound? if so, a cheap
> option may be to buy 2 more cheetahs for them! If it's the 4's, well how
> about a 2U U320 diskpack from whomever supplies you the Supermicro boxes?
Also, on the 4 drive machines if you can spare the room you might see a
big gain by putting the tables on one mirror and the OS and transaction
logs on the other.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461