[Linux-PowerEdge] poor disk IO - suggestions please?

Faris Raouf asterisk at raouf.net
Mon Jul 22 08:14:34 CDT 2013


Dear all,

 

I'm running a couple of R210 IIs with mirrored non-Dell-certified WD "Black"
500Gb 72k SATA on an H200 controller, with the write cache NOT enabled in
OMSA.

 

Disk performance in general always seemed sluggish on these compared to my
older R200s, but now it has started to become a serious problem, with high
IO Waits resulting in increasingly annoying issues for certain UDP-reliant
applications, particularly when we initiate backups. This just didn't happen
on the older machines.

 

I'm running a RedHat 6-derived 2.6.32-042 kernel (Parallels Virtuozzo) on
the R210 IIs and using the stock kernel mpt2sas driver.

 

I'm wondering if there would be a benefit to installing the dell-supplied
mpt2sas driver as opposed to using the stock kernel driver. Can anyone offer
any advice on this please? 

 

The kernel driver version is "12.101.00.00", while the latest Dell driver
for RH6 (64bit) is "07.00.01.00-1" and while 12.x is higher than 7.x, I
can't assume the version numbers are necessarily actually comparable, hence
my question here. I'm also concerned that the dell driver may be more tuned
to dell-certified drives than the stock kernel driver.

 

# modinfo mpt2sas

filename:
/lib/modules/2.6.32-042stab076.8/kernel/drivers/scsi/mpt2sas/mpt2sas.ko

version:        12.101.00.00

description:    LSI MPT Fusion SAS 2.0 Device Driver

author:         LSI Corporation <DL-MPTFusionLinux at lsi.com
<mailto:DL-MPTFusionLinux at lsi.com> >

vermagic:       2.6.32-042stab076.8 SMP mod_unload modversions

 

 

I'd love to enable the write cache (data centre has usual UPS + diesel
generators) but I'm somewhat worried about potential data loss/corruption if
I do - am I being over-cautious here? 

 

Switching to 10k or 15k SAS drives would be nice, but our budget prevents it
:(

 

I've also read an awful lot of posts in various places about how the H200
isn't great and so on, but that's what I've got so I have to make the best
of it. 

 

Any suggestions/hints would be appreciated!

 

 

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