ZFS performance issues (solved?!)
morganw at chemikals.org
Mon Sep 1 10:48:39 UTC 2008
On Mon, 1 Sep 2008, John Birrell wrote:
> For those people experiencing a performance degradation since the DTrace
> import, please update your copy of
> src/sys/cddl/compat/opensolaris/kern/opensolaris_kmem.c by either cvsup
> of direct edit to remove "#define KMEM_DEBUG".
> You only need to rebuild the opensolaris kernel module after this
> change. The code is shared between ZFS and DTrace via the opensolaris
> kernel module.
> This is also the reason why you found it necessary to add KDB, DDB and
> STACK to your kernel. After removing KMEM_DEBUG, you won't need those.
> Please confirm that this solves the problem you have been seeing.
8 or so hours later and everything is good here.
One other suggestion, the "opensolaris" module that is now required for
zfs is not mentioned anywhere in UPDATING. Users of "MODULES_OVERRIDE"
will likely find themselves with a system that will not boot without
manual intervention, sometimes even requiring a live cd. A headsup or
warning would probably be appreciated by other zfs'ers.
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