Date: Mon, 22 Nov 2010 12:49:54 +0200 From: Gleb Kurtsou <gleb.kurtsou@gmail.com> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: tmpfs out of space (ZFS related?) Message-ID: <20101122104954.GA2299@tops> In-Reply-To: <icc2ih$e5t$1@dough.gmane.org> References: <icc2ih$e5t$1@dough.gmane.org>
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On (21/11/2010 22:22), Ivan Voras wrote: > I got a curious error today while starting PostgreSQL, complaining about > "out of space" errno while creating lock file on /tmp. > > /tmp on this machine is mounted as tmpfs and indeed, here is the statistic: > > biggie:/# df -i > Filesystem 1M-blocks Used Avail Capacity iused ifree %iused > Mounted on > /dev/mfid0s1a 9912 5193 3926 57% 306079 1012831 23% / > devfs 0 0 0 100% 0 0 100% /dev > fdescfs 0 0 0 100% 4 11092 0% > /dev/fd > tmpfs 0 0 0 100% 9 0 100% /tmp > tank 376044 0 376044 0% 4 770138347 0% /tank > tank/ports 376658 614 376044 0% 145919 770138347 0% > /usr/ports > tank/mysql 376073 29 376044 0% 102 770138347 0% > /var/db/mysql > tank/pgdata90 400469 24425 376044 6% 1047 770138347 0% > /tank/pgdata90 > > On the other hand, "top" reports this: > > last pid: 79667; load averages: 0.08, 0.68, 0.77 up 1+09:12:13 > 00:11:33 > 44 processes: 1 running, 43 sleeping > CPU: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle > Mem: 13M Active, 46M Inact, 15G Wired, 232K Cache, 1458M Buf, 8358M Free > Swap: 1024M Total, 1024M Free > > Note the "8358M free" report. That's probably integer overflow, could you try specifying max size as mount option. There was a series of integer overflows in tmpfs. Used and available are 0 in df output. On my system I have: % df Filesystem Size Used Avail Capacity Mounted on tmpfs 4.3G 4.0K 4.3G 0% /usr/obj/ports Also note, that tmpfs does somewhat weired thing on constantly recalculating available space based on free memory/swap (not sure if specifying max size would fix it). Did you try double copy elimination patch by kib@? http://lists.freebsd.org/pipermail/freebsd-fs/2010-June/008786.html It doesn't apply cleanly to current any more, but fixing it shouldn't be hard. The patch wouldn't fix this particular issue but looks very promising. Thanks, Gleb > The server has ZFS and was doing IO intensive database work on it; the 8 > GB free memory comes from PostgreSQL being restarted and freeing the > memory (but failing to start again...). > > Starting PostgreSQL gets me this message: > Nov 22 00:18:24 biggie postgres[79696]: [1-1] FATAL: could not write > lock file "/tmp/.s.PGSQL.5432.lock": No space left on device > > This is 8-STABLE amd64. > > Running "touch /tmp/abc" works, and creates a file. Running "echo abc > > /tmp/abc" doesn't return an error but *doesn't write anything to the > file*, just creates a directory entry. > > The status doesn't change over time, i.e. "df" on tmpfs always shows "0 > free". > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"
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