RHEL3 and SAS5/iR: very bad performance

Giulio Orsero giulioo at gmail.com
Wed Jan 24 07:40:22 CST 2007

RHEL3 + mpt 2.06.32 driver.

Using same PE840 system (Celeron2.8 1GB), we perform some tests with:

	1) simple SATA 120GB disk connected to motherboard
	2) SAS5/iR with 2x160GB SATA disks in RAID1 

Case #1 (simple SATA disk):
- bonnie (file=RAMx2): about 70MB/s writes, about 80MB/s reads
- custom database app (write data):  
	job1 = 5 mins	
	job2 = 20 mins

Case #2 (SAS5/iR DRV 2.06.32 FW- BIOS-
- bonnie (file=RAMx2): about 40MB/s writes, about 120MB/s reads
- custom database app (write data):  
	job1 = 15 mins
	job2 =  4/5 hours  (yes hours instead of 20mins, this is db rebuilding

Is there some magical module parameters (mptbase or mptscsih) or compile
time switch to give SAS5/iR some decent performance in writes?
I can't believe this is normal behavior.

If possible don't tell me to switch to PERC5 :-)
Before buying many SAS5/iR, Dell tech person assured me performance in RAID1
is basically the same on SAS5/iR and PERC5 as far as hardware is concerned.

giulioo at pobox.com

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