Smart Array 5304 Peformance considerations

[Jörg-Stefan Sell]

I have a Raid 5 with 10 hard drives in a 4300 enclosure attached to a Smart Array 5304 with 128MB of cache.

Here's my question: Will I see a performance increase of the logical drive if I arrange the drives in two different 4300s, each attached to a different port on the controller?

Thanks in advance,
Jörg-Stefan

[e4services]

sometimes.
Performance is all relative.
Usage, application, etc. Adding a cahe module is the most dramatic basic performance increase, giving some breathing room for writing the RAID.

[Jörg-Stefan Sell]

I finaly had the time to give it a try:

Before, a single threaded Disk I/O tool showed a 45MB/sec write rate and a 72MB/sec read rate; after moving half of the drives to a second enclosure attached to port 3 the read rate increased to 85MB/sec, write performance did not show any change.

[Steven Clementi]

Jörg:

Thats sounds about right. You should expect to see a read performance since you are now utilizing more of the card's buses instead of taxing a single bus.

As for Writing, I would expect that you would see a bigger difference on a more intensive test, but simple writes would probably not show much change.

Can you perform another test assuming you have the time, this time try copying or moving a large amount of data. If you did this already in the initial test, then just disregard.


Steven

[Jörg-Stefan Sell]

Thanks for your response, Steven.

What do you consider a larg file? I did my initial tests with 500MB files...

I personaly would have expected that the 33Mhz slot in which the 5304 is located is a bottleneck, it's obviously wrong, I would say.

What do you think, will I see an additional performance increase if I move the controller to a machine with a 66Mhz PCI slot?

What concerns me a bit: During disk I/O the system time shown by Windows Task manager (W2K3+SP1) significantly increases, about 25% on a four way system. Firmware and drivers are up to date... Is this a normal, expected behaviour?

Is there any documentation from HP which covers this disk I/O performance topic in more detail?

[Jacob Zeeman]

Hi Jorg,

I don't want to disagree with any of the previous replies. However if you plan on spanning a single logical drive/array onto two different SA4300 controllers you will likely not be able to access your storage.

This is because you are unable to span an array to mulitple controllers, you can only span channels. With the SA5304 all four ports are on the same controller.

Just wanted to give you a warning before you attempt this process.

(Sorry if someone already covered this. I didn't look too thoroughly at the previous posts.)

Jake Zeeman
HP Server Storage

[Jörg-Stefan Sell]

Don't worry, the scenario is one controller with multiple enclosures, not the other way.

But many thanks for your attention!