On Sun, 23 Mar 2014, Reginald Beardsley wrote:
Some casual testing has turned up a bit of a puzzle.
I've got an N40L w/ 4x2TB ST2000DM001 in a RAIDZ2 pool with 4 GB of ECC DRAM
running oi151a7. This is NFS mounted to a Z400 running Solaris 10 (last Sun
release U7?)
On the N40L I get 125 MB/s write and 250 MB/s read for 6.5 GB using /dev/zero &
/dev/null w/ bs=65536.
On the Z400 using NFS I get 50 MB/s write but only 10-20 MB/s read for the same
operations. Both systems and the network are unloaded. Write speed over NFS
is quite consistent, but the read varies by 2x.
Can anyone suggest why the NFS read is so much slower than the NFS write? I'm
baffled by the relative speed of the R/W operations reversing like that. The
only reasons I can think of are some issue in the network stack or NFS
implementations.
You have not really told us very much. What mechanism/approach are
you using to measure client NFS read and write performance on the
Solaris 10 system?
Bob
--
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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