Craig A. James wrote:
I'm experiment with RAID, looking for an inexpensive way to boost
performance. I bought 4 Seagate 7200.9 120 GB SATA drives and two SIIG
dual-port SATA cards. (NB: I don't plan to run RAID 0 in production,
probably RAID 10, so no need to comment on the failure rate of RAID 0.)
I used this raw serial-speed test:
time sh -c "dd if=/dev/zero of=./bigfile bs=8k count=1000000 && sync"
(unmount/remount)
time sh -c "dd if=./bigfile of=/dev/null bs=8k count=1000000 && sync"
Which showed that the RAID 0 4-disk array was almost exactly twice as
fast as each disk individually. I expected 4X performance for a 4-disk
RAID 0. My suspicion is that each of these budget SATA cards is
I am assuming linux here, Linux software raid 0 is known not to be super
duper.
Secondly remember that there is overhead involved with using raid. The
direct correlation doesn't work.
Joshua D. Drake
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/
