Redundant NFS storage setup (part 3) : The disappointing PERC5/E (solved?)

[Harald_Jensas at Dell.com]

Matthias Saou wrote :

 [...]
> I just tested again with the partition starting at the very beginning
> (17.4kB) and 128kB, both give 280-300MB/s depending on the run. As a
> wild guess, I just tried starting at 64kB and got 550-560MB/s with
> hdparm, while I have my RAID5 configured with 128kB stripe size...
> 
> With iozone on that partition, I see no significant changes, but my
> "real world test" of sequential reads now manages to get 480-550MB/s
> sustained for 3 non cached 10GB files, which is the highest I've ever
> seen with this setup.
> 
> But really, why starting the partition at 64kB gives me the best
> results
> while my RAID5 has a 128kB stripe size is beyond me. I'm glad I tried
> it, though ;-)
> 
> Matthias
> 

Hi,

Great to hear that you had improvements! I cannot explain it. :)

I have looked over my reasoning again, but I cannot see the mistake. I
am sure there is something I missed/misunderstood though.


--
Harald