We recently acquired two "decked out" DL360's, complete with the Smart Array P400i RAID raid controller, 512MB BBWC, and (6) 10k SAS drives.
They are configured in a RAID 1+0 set up, running LVM and ext3.
Using the HP utilities (hpacucli), I set up the disk write cache (to be on), and the accelerator cache ratio to be 25% write, and 75% read.
I've also updated them to the latest firmware using the HP firmware disk (version 7.22 of the RAID firmware).
In looking around the web, I found this link: http://www.overclock.net/hard-drives-storage/515068-tuning-hp-smart-array-p400-linux.html
Which shows that with the read-ahead set properly, one can achieve some fairly amazing performance.
My own tests (same iozone performance) shows:
Initial write 191148.89 191.15 Rewrite 204751.79 204.75 Read 127655.03 127.66 Re-read 126286.11 126.29 Random read 148323.94 148.32 Random write 185377.55 185.38
Most of my read numbers are 1/2 to 1/3 of the numbers being reported by (8) SAS drives, with xfs.
What am I missing? Does xfs and (2) drives make that much of a difference? Or, did I not configure something?
Any, lastly ... would software RAID be faster?