Date: Thu, 29 Oct 1998 21:29:10 -0800 From: Mike Smith <mike@smith.net.au> To: Peter Jeremy <peter.jeremy@auss2.alcatel.com.au> Cc: hackers@FreeBSD.ORG Subject: Re: sync writes with softupdates enabled Message-ID: <199810300529.VAA00927@dingo.cdrom.com> In-Reply-To: Your message of "Fri, 30 Oct 1998 16:21:51 %2B1100." <98Oct30.162123est.40365@border.alcanet.com.au>
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> I've just installed 3.0-RELEASE on the machine destined to be our new > news server. Whilst testing it with soft updates enabled, I'm seeing > a lot of sync writes onto /usr: > > /dev/wd0s1f on /usr (local, soft-updates, writes: sync 32910 async 4955) > > With /usr mounted asynchronously rather than soft updates enabled, > I also saw lots of synchronous writes. > > The writes are definitely a result of innd - nothing else much is > running and pausing innd makes the I/O stop. I've looked at a > ktrace of innd and can't see anything that would obviously cause it > to do sync writes (no fsync() or open(O_SYNC) calls). > > It's inn-1.7.2 as per the ports with the exception that MMAP is > enabled for dbz. > > All I can think of is that the MMAP'd history file is causing the > kernel to unnecessarily perform sync writes to try and keep the > MMAP and VFS images in sync. That's almost certainly correct. Try running without mmap. It used to be faster that way; maybe it is again? -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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