Slow IO on a HP DL180...

[Vini]

I've just started a new job and have been tasked with troubleshooting a server with less than desirable performance.

It's a DL180 G5, with 16Gb of RAM which shipped with a Smart Array E200 (128Mb) controller, of which there are another 9 identical boxes that are working absolutely fine! Unfortunately I am unable to power any of the other units off to aide with my troubleshooting, so...

I've tried;
-updating DL180 firmware/bios (already on the latest)
-updating the E200 firmware/bios (needs to be in Windows, but performance is that bad I can't even get in!)
-reinstalling windows
-rebuilding the array

I've had a little bit of luck with;
-replacing the E200 SA with a P400 SA (256Mb)


The unit is setup in Raid 1. Performance looks like this (as you can see, it is the writing that appears to be causing problems!);



Admittedly, performance since changing the controller is massively improved. Heck, I left windows installing on Friday using the E200 and I came back on Monday to find it at 39%. With the P400 installed, I was able to install Windows and set benchmarks running yesterday!

Any things I could check?

[Vini]

There's no BBWC on the P400, so I've put the E200 back in and replaced the onboard BBWC (which was whinging about low battery!) and I've enabled Write Cache... It's running more benchmarks now.

Fingers crossed!

[Steve]

What disks are in there?

I've seen 4K sector issues cripple write performance (as a 512b write turns into a 4k read/modify/write).

[shaithis]

Also.....I know it's an order of magnitude greater then you would expect but check partition alignment anyway.

[Vini]

The drives are Dell Cheetah's 15K, SAS. Will look into sectors & partition alignment today. CheerS!

[Vini]

The drives are Dell Cheetah's 15K, SAS. Will look into sectors & partition alignment today. CheerS!

Replaced the BBWC, rebuilt the raid and retried;




It's like having a set of SSD's in there compared to earlier!

[Steve]

Excellent!