Date: Thu, 31 May 2012 19:27:19 -0400 From: Daniel Staal <DStaal@usa.net> To: Dennis Glatting <dg@pki2.com> Cc: freebsd-questions@freebsd.org Subject: Re: Anyone using freebsd ZFS for large storage servers? Message-ID: <70D99F583BF63C05BB39CCAF@mac-pro.magehandbook.com> In-Reply-To: <alpine.BSF.2.00.1205311102290.48219@btw.pki2.com> References: <CACxnZKM__Lt9LMabyUC_HOCg2zsMT=3bpqwVrGj16py1A=qffg@mail.gmail.com> <alpine.BSF.2.00.1205311102290.48219@btw.pki2.com>
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--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" 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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