On Mon, 31 May 2010, Matt Connolly wrote:
Watching `zpool iostat -v 2` I could see that quite often drive 1
would write a big chunk of data and then wait for ages for drive 2
to write the same data to disc.
Could it be that there is a separate cache for the mirror that was
stalling waiting on the cache for the larger drive??
Would this scenario be caused because the drives are so different in
size? 250GB and 1500GB??
I think that the problem is likely that this Western Digital drive is
one of the new ones using 4K sectors internally. Almost everyone
obtains terrible write performance from zfs using these drives. I
suggest getting rid of it and replace it with a drive which still uses
standard 512 byte sectors internally. It will be like night and day.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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