Does these performance readings look accurate?

[jcazes]

I have been suspecting my RAID 5 setup to be slower than it should, but don't know what is the norm. Below is a screenshot of my hdtune readings from the array:


(Adaptec 4805SAS w/ 4x500GB WD RE drives [specs in sig])

And this is my (seemingly) normal raptor:

Are these transfer times accurate for the RAID5 array?

 

[unhappy_mage]

Are you using this on a PCI bus? If so, that looks normal.

Edit: Wow, no. That's an x8 card. It could just be Adaptec's fault, or something could be wrong.

 

[jcazes]

Yeah, it's in an 8x electrical slot (on my D975XBX2), so I'm a little baffled (even though I don't know what kind of numbers I should be seeing ).

I think I will give adaptec a call tomorrow.

 

[Madwand]

Try using HDTune 2.54 -- it uses a larger block size by default and also allows you to change it.

Try using IOMeter for a file system level test. E.g. configuration:

http://www.infrant.com/forum/viewtopic.php?t=265

I suggest increasing the test size 10x and also including 64k accesses.

 

[drizzt81]

they look like they are on the low end, since a 4disk R-5 array should provide raw read speeds in the neighborhood of a 3-disk R-0 array.

 

[jcazes]

Didn't get a chance to call Adaptec (their business hours almost coincide with my work schedule), but just ran both tests you requested:

 

[Madwand]

Doesn't look too good. Perhaps turning on some caching might help? I'm not familiar with your controller, so don't have specific advice.

As another suggestion, you could try ramping up the access size and then increasing the concurrent I/O request count in IOMeter to see how the card behaves under those conditions. Maybe it's better tuned for concurrent access than sequential.

If you have the time and no significant data on the array yet, you could try setting up a similar array using the on-board ports to see how that fares in comparison.

 

[shade_star]

Agreed - with 4 drives your array is slow. What stripe size?

 

[jcazes]

stripe size is 256k. I will admit, there are some gaps in my RAID knowledge, and one of them is stripe sizes...


Anyway, I updated the bios on my mobo and RAID controller, and have seen some drastically different results in HDtune.

It still takes about 2 minutes for the controller kernel to load on system-boot, so I still have some questions (which should now be issues Adaptec should be able to answer now that I have latest bios).