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RAID 5i performance

Jon Schneider
Occasional Advisor

RAID 5i performance

We've bought a DL380 with a RAID 5i card and four disks (three of which are active in a RAID 5 array)

and find the throughput really disappointing even with the new driver HP released on Sunday 1st. The machine is running RHEL 3.

# time dd bs=1024k if=/dev/cciss/c0d0p2 of=/dev/null count=100 skip=2000
100+0 records out

real 0m2.352s

itebox).

ie. about 42MB/s when I'd expect two disks' worth.

We asked the dealer to do a test on a windows machine with similar kit and it is just as bad.

It seems the machine/controller/driver combination is bad (or the disks fell off the back of a lorry).

Could I ask for an official HP response to this. Also that anybody else test the performance of this hardware use with RAID5.

Jon

P.S. Could the webperson enlarge the silly little box I am typing into please.
12 REPLIES
Doug de Werd
Honored Contributor

Re: RAID 5i performance

This has been discussed here several times.

Basically it's a combination of RAID 5 with only 3 disks and not having the Battery Backed Write Cache (BBWC) for the 5i.

Check some of these previous discussions:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=650277

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=206252

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=200118


Thanks,
Doug
Expert in ProLiant Clusters
Jon Schneider
Occasional Advisor

Re: RAID 5i performance

The links Doug suggests show that

* other people have the same problem

* the write cache thing has no effect on read performance which is what I'm asking about

* this controller does indeed seem to be awful and cannot match what can be knocked up with software RAID and a fraction of the money

Jon
Nathan Gervais
Trusted Contributor

Re: RAID 5i performance

Jon,

Is the 5i at the latest firmware revison? 2.58a?

http://h18007.www1.hp.com/support/files/server/us/download/20142.html

It has a fix in it that may pertain to your issue. :

Fixed a problem that unnecessarily caused drives to downshift to slower speeds.
Jon Schneider
Occasional Advisor

Re: RAID 5i performance

When it boots it mentions 2.58 (no A).

It is unclear from the changelog whether they fixed the problem with the addition of the A or earlier.

Right now the server is being used on a live website so I can't down it (again).

Does anybody from HP actually participate in this forum in an official capacity ? It would save a lot of wasted time.

Jon
Jon Schneider
Occasional Advisor

Re: RAID 5i performance

I downloaded the file from the 2.58A firmware page and ran it.

It said I already had 2.58 so I ran it with the force option which succeeded.

I rebooted. There was no performance improvement.

Jon
Andy_180
Trusted Contributor

Re: RAID 5i performance

Embedded is not the best answer. stock anything is very basic. if performance is what your looking for, use a 632, 6404.

However I have a 380G2 supporting 285 users as a DMS. and it is 6 36.4 B drives RAID 5 and running off of the 5I. no one has ever complained of slowness saving or checking out documents. perhaps you should review your configuration.

I guess you really never said which 380 you purchased. G2 would best be suited with a 5300 series. those are U160 and the g3's are U320.

Try updating the firmware on the embedded controlellers on the SCSI HDs.
Jon Schneider
Occasional Advisor

Re: RAID 5i performance

> no one has ever complained of slowness
> saving or checking out documents.

I'm interesting in pumping gigabyte files not word documents !

Jon
Doug de Werd
Honored Contributor

Re: RAID 5i performance

Bottom line is that the integrated 5i Smart controller is a basic controller that is primarily intended for providing simplified HW RAID and average performance (think boot drives). If you want max performance you need to upgrade to a PCI based Smart Controller (53xx/64xx, etc.)

Thanks,
Doug
Expert in ProLiant Clusters

Re: RAID 5i performance

You're kidding, right?

42 MB/s is comparable to old ATA drives such as Seagate Barracuda ATA IV, and you don't think a Raid 5 set of new 10k RPM SCSI drives should perform better?

Sør

Re: RAID 5i performance

ROM 2.58B is out, anybody tried it??

According to the list of fixes, the only difference is a problem with MSA20, but you never know.

And "naturally" it reports itself as 2.58 (both when you install, and at boot time), so you have to force it to install and remember which version of 2.58 you have installed...

Nice work, HP...
Jon Schneider
Occasional Advisor

Re: RAID 5i performance

I've now realised what "HP invents" actually refers to.

Controller specifications
Version numbers

Jon

Re: RAID 5i performance

By controller specs, I guess you're referring to the 160 MB/s per channel that the 5i supposedly should be capable of?