Date: Mon, 1 Sep 2008 03:52:57 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Wes Morgan <morganw@chemikals.org> Cc: stable@freebsd.org, John Birrell <jb@what-creek.com> Subject: Re: ZFS performance issues (solved?!) Message-ID: <20080901105257.GA4269@icarus.home.lan> In-Reply-To: <alpine.BSF.1.10.0809010539210.52681@ibyngvyr.purzvxnyf.bet> References: <20080901021528.GB56694@what-creek.com> <alpine.BSF.1.10.0809010539210.52681@ibyngvyr.purzvxnyf.bet>
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On Mon, Sep 01, 2008 at 05:48:34AM -0500, Wes Morgan wrote: > 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. I second this motion. Upon rebuilding my system this morning, I was surprised to see the kernel printf()s about OpenSolaris and CDDL, and could find no mention of what purpose the module served. I'm assuming it's a module with some centralised code-pieces that DTrace and ZFS share, but I don't have any confirmation of this. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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