On 15 Nov 07, at 1504, Michael Bacon wrote:
Interesting thought. We haven't gone to ZFS yet, although I like
the idea
a lot. My hunch is it's an enormous win for the mailbox
partitions, but
perhaps it's not a good thing for the meta partition. I'll have to
let
someone else who knows more about ZFS and write speeds vs. read speeds
chime in here.
We're finding it a real win for the meta-partition. We're handing
~1000 users on a 2-way stripe by two-way mirror on the internal disks
in a T2000 for the meta-data, with the message data coming in over
NFS. We do see a few spikes of write operations (this is one
instance from zpool isotat -v 1):
capacity operations bandwidth
pool used avail read write read write
------------ ----- ----- ----- ----- ----- -----
pool1 52.1G 25.9G 4 657 3.96K 3.71M
mirror 26.0G 13.0G 4 354 3.96K 1.42M
c0t0d0s4 - - 0 135 0 1.42M
c0t1d0s4 - - 0 126 63.4K 1.42M
mirror 26.0G 13.0G 0 302 0 2.29M
c0t2d0s4 - - 0 112 0 2.29M
c0t3d0s4 - - 0 109 0 2.29M
------------ ----- ----- ----- ----- ----- -----
but it's showing no signs at all of being IO bound on the metadata.
The spikes are really just spikes for a second: the typical level is
about 10 ops / disk / sec.
ian
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