Date: Thu, 31 May 2012 17:34:12 -0700 From: Dennis Glatting <freebsd@pki2.com> To: Daniel Staal <DStaal@usa.net> Cc: freebsd-questions@freebsd.org Subject: Re: Anyone using freebsd ZFS for large storage servers? Message-ID: <1338510852.77553.1.camel@btw.pki2.com> In-Reply-To: <70D99F583BF63C05BB39CCAF@mac-pro.magehandbook.com> References: <CACxnZKM__Lt9LMabyUC_HOCg2zsMT=3bpqwVrGj16py1A=qffg@mail.gmail.com> <alpine.BSF.2.00.1205311102290.48219@btw.pki2.com> <70D99F583BF63C05BB39CCAF@mac-pro.magehandbook.com>
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On Thu, 2012-05-31 at 19:27 -0400, Daniel Staal wrote: > --As of May 31, 2012 11:24:41 AM -0700, Dennis Glatting is alleged to have > said: > > > 2) Under heavy I/O my systems freeze for a few seconds. I haven't looked > > into why but they are completely unresponsive. Note I am also using > > compressed volumes (gzip), which puts a substantual load on the kernel. > > --As for the rest, it is mine. > > I'm not using as huge a dataset, but I was seeing this behavior as well > when I first set my box up. What was happening was that ZFS was caching > *lots* of writes, and then would dump them all to disk at once, during > which time the computer was completely occupied with the disk I/O. > > The solution (suggested from <http://wiki.freebsd.org/ZFSTuningGuide>) for > me was: > vfs.zfs.txg.timeout="5" > Was already set: mc# sysctl vfs.zfs.txg.timeout vfs.zfs.txg.timeout: 5 > in loader.conf. That only allows it to cache writes for 5 seconds, instead > of the default 30. This appears to be the default in the latest versions > of FreeBSD, so if you are running an upgraded 9, ignore me. ;) (But check > the page linked above: There are other suggestions to try.) > > Daniel T. Staal > > --------------------------------------------------------------- > This email copyright the author. Unless otherwise noted, you > are expressly allowed to retransmit, quote, or otherwise use > the contents for non-commercial purposes. This copyright will > expire 5 years after the author's death, or in 30 years, > whichever is longer, unless such a period is in excess of > local copyright law. > ---------------------------------------------------------------
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