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

[Matthias Saou]

Hi all,

Looking for information on XFS filesystem options, I found this very
instructive thread :

http://oss.sgi.com/archives/xfs/2007-09/msg00322.html

I read about this simple change in one of the posts, which improved
performance a lot for the person making the benchmark, so I ran it :
# blockdev --setra 16384 /dev/sdb

I now get 500-520MB/s read speed with hardware RAID5 where I used to
get 30-35MB/s... pretty amazing, I must admit.

Looking at the man page, this just sets a read-ahead value... I'm
puzzled yet very happy!

Would any of the others who reported slow read speeds with their PERC5s
and MD1000s care to also try it and report back to the list?

I'll continue digging, but in the meantime, it seems like my "problem"
might be solved.

Matthias

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