Poor read speeds w/ Raid. Advice?

[Codeman05]

Working on a setup for a friend using 4x Maxtor 200GB 7200rpm 8mb cache drives in RAID 0 (don't worry, he has another drive for backing up data, so lets not debate that).

I have attached the ATTO results.
The Write speeds are superb, but the Read speeds are a little disappointing, not sure why it drops so much at the 8k and starts over.

I'm not sure what the stripe is set as...is there anyway to check? Going into the raid bios did not tell me unfortunately.

Would changing the stripe size "balace" the read/write better, or atleast improve the Read speed a bit.

Thanks

 

[Snugglebear]

Increase the transfer set sizes and the total size of the test transfers. RAID0 stripesets don't do well unless they're dealing with a lot of contiguous data since the drives operate asynchronously. Running HDTach would also be a good way to see what the contiguous read performance over a large data set is like. Writes should show up as incredibly fast until the buffers on the drives are filled, so these small tests are just being performed in cache (via write acceleration).

If the tests are still showing low read speeds after retesting with larger data sets, check into any known deficiencies with the drive firmware and running the units in stripesets. You may have luck finding a RAID management tool that can tell you the stripe size - one may be published by the controller's manufacturer. Adaptec, LSI, and Intel have them, but I don't follow other manufacturers that well.

 

[shadowdr]

Change total length to 32 and que depth to 10.Run at least twice as results like you posted can just be a quirk and can happen on a first run when changing total length or que depth.