Date: Fri, 02 Nov 2007 15:10:03 +0100 From: Marek Blaszkowski <mb@kis.p.lodz.pl> To: freebsd-amd64@freebsd.org Subject: Re: strange i/o and tty lockups/delays on 6.1, strange sync() issue Message-ID: <472B2FBB.5070308@kis.p.lodz.pl> In-Reply-To: <Pine.LNX.4.64.0710311048450.31199@knuth.cs.hmc.edu> References: <4728906E.8020804@kis.p.lodz.pl> <Pine.LNX.4.64.0710311048450.31199@knuth.cs.hmc.edu>
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Nate Eldredge wrote: > On Wed, 31 Oct 2007, Marek Blaszkowski wrote: > >> Hi, >> my config: >> thunder k8sr, dual opteron 244, 8GB RAM, FreeBSD 6.1, sata disk >> >> >> for time to time (every 10 or 20 secs) any process which try write or >> read any, even small file, is locked for a couple seconds (about 7 or >> 9 secs), very iritating when I try save small files edited in vim >> (size about 2-3 kbytes), it's looks like this: #vim /path/to/file >> ...editing.. >> :w >> and now (afetr w command) vim freeze for 7-10 secs until it displays >> "file written". >> >> Delays accours on tty, too. In vim I can't move around edited file >> (up/down in rows), vim just got hang, strange is that I can switch >> (durning vim lockup) beetwen virtual screen consoles. > > > [sync takes a long time too] > > Is there anything in the log files? This might happen if the disk > access fails or times out; the kernel resets the controller and tries > again, which takes a long time. That would indicate that the disk is > probably failing, in which case it should be backed up and replaced as > soon as possible. You could also see if smartctl reports anything > significant. > > If that's not it, you might try running top and see if any process > accumulated CPU seconds during the hang. > > I experienced a couple of other issues where things would hang > momentarily. One was fixed by disabling ACPI (it's a long story) and > the other by enabling PREEMPTION. So if the disk is okay those are two > more things you could try. > > Hope this helps. I'd be interested to know what you find out. Does PREEMPTION option is safe for production servers now? I saw many threads on amd64@ or stable@ about kernel crashes with this option enabled, so I don't decided to use it... regrads, -- Marek B.
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