Date: Thu, 8 Mar 2012 17:50:51 +0000 From: Tom Evans <tevans.uk@googlemail.com> To: Dan Rue <drue@therub.org> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS and mdconfig -t vnode - Unexpected behavior Message-ID: <CAFHbX1KkonKGyjgYBMxj=-Kn9GNdKr%2BT5GYDMvhNo-Deq6BUsA@mail.gmail.com> In-Reply-To: <20120308161940.GA71851@therub.org> References: <20120308161940.GA71851@therub.org>
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On Thu, Mar 8, 2012 at 4:19 PM, Dan Rue <drue@therub.org> wrote: > I have discovered an unexpected behavior when using ZFS against a vnode. > When running mdconfig -d against a vnode, there is a long delay before > the blocks are fully written to the backing store file. Consider the > following test script: > > [=E2=80=A6] > > Are there any ZFS tunables that could be related to this? What could be > the cause of this behavior? > The tunable vfs.zfs.txg.timeout (in seconds) controls how bursty ZFS is. I run with a high value (30), so my disks don't get constantly hit, but if you lowered it, data will be written much more frequently. Cheers Tom
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