Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have 2 Dell pe2950 with a raid5 configuration. They are identical inconfiguration, however if I do a harddisk benchmark with ATTO Disk Benchmark I get very strange results.

Both machines are of type III and have a perc5/i controller with 6 3.5" 2TB harddisks in raid5 configuration with one hotspare. I Tried raid 50 before, but that configuration didn't seem to work at all. Now the dfs3 machine actually randomly doesn't respond when I start the ATTO benchmark.

So I can't post the images since I do not have a 10 credit reputation but it comes down to this:

0.5kb  w:9679 r:8596
32kb   w:172164 r:257838
64kb   w:197287 r:282699
128kb  w:212813 r:302921
256kb  w:200324 r:389389

0.5kb  w:4213 r:91428
32kb   w:233510 r:1533739
64kb   w:394182 r:1830975
128kb  w:401649 r:2011693
256kb  w:429531 r:2080374

The numbers for write and read tranfer rates are in MB/sec. The differences are huge. For 128kb block read access the DFS3 has a max throughput of 302921 (this can't be right) but the DFS4 reaches speeds of 2011693 (I'm sure there is a bug in the UI saying MB/sec). But still its 10x as much.

Also, the DFS3 sometimes just stops working then I start these benchmarks.

Anyone encountered a similair problem?

Regards, Joham

share|improve this question
what about BIOS settings/version, firmware version? – ALex_hha Jul 23 '13 at 13:33
Are the drives EXACTLY identical? Or maybe the system image shipped with differing drivers (ie. chipset drivers). – Bigbio2002 Jul 23 '13 at 13:37
when you say identical do you mean in both hardware and software terms? – tony roth Jul 23 '13 at 13:44
yes bios is the same and drives are the same (i bought them in one go). I also looked for hdd firmware updates but found nothing for the WDCWD2000FYYZ0. I enabled adaptive read ahead and write back on both controllers/machines. both have the same and latest bioses and firmware too. – Johannes Jul 23 '13 at 13:45
the problem is that the dfs4 is already in production, but I wanted to create a clustered configuration when I found these strange results on the dfs3. – Johannes Jul 23 '13 at 13:46

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.