Date: Sat, 26 Jan 2013 01:30:01 GMT From: Harry Coin <hgcoin@gmail.com> To: freebsd-fs@FreeBSD.org Subject: Re: kern/169480: [zfs] ZFS stalls on heavy I/O Message-ID: <201301260130.r0Q1U1QA033345@freefall.freebsd.org>
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The following reply was made to PR kern/169480; it has been noted by GNATS. From: Harry Coin <hgcoin@gmail.com> To: bug-followup@FreeBSD.org, levent.serinol@mynet.com Cc: Subject: Re: kern/169480: [zfs] ZFS stalls on heavy I/O Date: Fri, 25 Jan 2013 19:26:10 -0600 I think I have an easier way to reproduce this problem on a very simple setup: Boot a 'nas4free' livecd version 573 (freebsd 9.1.0.1). Mount one zpool with no dedup, simple raidz 4 drive setup, 4GB memory. Don't enable any of the various features, just get a shell from the live cd prompt. Use dd to make a 20GB file on the pool writing from /dev/random. While that's going, go to another virtual console cd to the pool, and do an ls -l. It won't return. Of interest, long before wired memory explodes to the limit, ls not returning while dd is running, 'top' on another shell reports this: 99.7% idle, 2.6gb free ram, dd in tx->tx, zfskern in zio->i, and intr in WAIT Eventually disk activity as shown by the cheery little flickering lamp slows, then stops. Characters still echo on the ls -l command that hasn't returned, but no others. alt-tab strangely still works. The only way out is to power cycle the box. Details here: http://forums.nas4free.org/viewtopic.php?p=12519#p12519 Feels like completed io's are getting lost and the system just waits and waits until there are no more resources left to issue new commands or too many threads are locked waiting for what will never return. Harry
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