On Thu, May 21, 2009 at 2:29 PM, Robert Haas <robertmhaas@xxxxxxxxx> wrote: > On Thu, May 21, 2009 at 8:59 AM, Matthew Wakeling <matthew@xxxxxxxxxxx> wrote: >> On Thu, 21 May 2009, Linos wrote: >>> >>> i have to buy a new server and in the budget i have (small) i have >>> to select one of this two options: >>> >>> -4 sas 146gb 15k rpm raid10. >>> -8 sas 146gb 10k rpm raid10. >> >> It depends what you are doing. I think in most situations, the second option >> is better, but there may be a few situations where the reverse is true. > > One possible case of this - I believe that 15K drives will allow you > to commit ~250 times per second (15K/60) vs. ~166 times per second > (10K/60). If you have a lot of small write transactions, this might > be an issue. But in a RAID-10 you aggreate pairs like RAID-0, so you could write 250(n/2) times per second on 15k where n=4 and 166(n/2) for 10k drives where n=8. So 500 versus 664... ? Or am I getting it wrong. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
