Date: Fri, 21 Jul 2006 14:00:05 +0100 From: Feargal Reilly <feargal@fbi.ie> To: freebsd-stable@freebsd.org Subject: filesystem full error with inumber Message-ID: <20060721140005.5365e4b7@mablung.edhellond.fbi.ie>
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The following error is being logged in /var/log/messages on
FreeBSD 5.4:
Jul 21 09:58:44 arwen kernel: pid 615 (postgres), uid 1001
inumber 6166128 on /data0: filesystem full
However, this does not appear to be a case of being out of disk
space, or running out of inodes:
ttyp2$ df -hi
Filesystem Size Used Avail Capacity iused ifree
%iused Mounted on
/dev/amrd0s1f 54G 44G 5.4G 89% 4104458 3257972
56% /data0
Nor does it appear to be a file limit:
ttyp2$ sysctl kern.maxfiles kern.openfiles
kern.maxfiles: 20000
kern.openfiles: 3582
These reading were not taken at exactly the same time as the
error occured, but close to it.
Here's the head of dumpfs:
magic 19540119 (UFS2) time Fri Jul 21 09:38:40 2006
superblock location 65536 id [ 42446884 99703062 ]
ncg 693 size 29360128 blocks 28434238
bsize 8192 shift 13 mask 0xffffe000
fsize 2048 shift 11 mask 0xfffff800
frag 4 shift 2 fsbtodb 2
minfree 8% optim time symlinklen 120
maxbsize 8192 maxbpg 1024 maxcontig 16 contigsumsize 16
nbfree 563891 ndir 495168 nifree 3245588 nffree 19898
bpg 10597 fpg 42388 ipg 10624
nindir 1024 inopb 32 maxfilesize 8804691443711
sbsize 2048 cgsize 8192 csaddr 1372 cssize 12288
sblkno 36 cblkno 40 iblkno 44 dblkno 1372
cgrotor 322 fmod 0 ronly 0 clean 0
avgfpdir 64 avgfilesize 16384
flags soft-updates=20
fsmnt /data0
volname swuid 0
Now the server's main function in life is running postgres.
I first noticed this error during a maintainence run
which sequentially dumps and vacuums each individual database.
The are currently 117 databases, most of which are no more than
20M in size, but there are a few outliers, the largest of which
is 792M in size. The chunk of this is stored in a single 500+M
file, so I can't see this consuming all my inodes, even if
soft-updates weren't cleaning up, perhaps I'm wrong. It has
since been happening outside of those runs as well.
I have searched through various forums and list archives, and
while I have found a few references to this error, I have not
been able to find a cause and subsequent solution posted.
Looking through the source, the error is being logged by
ffs_fserr in sys/ufs/ffs/ffs_alloc.c It is being called either
by ffs_alloc or by ffs_realloccg after either of the following
conditions:
ffs_alloc {
...
retry:
if (size =3D=3D fs->fs_bsize && fs->fs_cstotal.cs_nbfree =3D=3D 0)
goto nospace;
freespace(fs, fs->fs_minfree) - numfrags(fs, size) <
0) goto nospace;
...
nospace:
if (fs->fs_pendingblocks > 0 && reclaimed =3D=3D 0) {
reclaimed =3D 1;
softdep_request_cleanup(fs, ITOV(ip));
goto retry;
}
ffs_fserr(fs, ip->i_number, "filesystem full");
}
My uninformed and uneducated reading of this is that it does not
think there are enough blocks free, yet that does not tally with
what df is telling me.
Looking again at dumpfs, it appears to say that this is formatted
with a block size of 8K, and a fragment size of 2K, but
tuning(7) says:
FreeBSD performs best when using 8K or 16K file system
block sizes. The default file system block size is 16K, which
provides best performance for most applications, with the
exception of those that perform random access on large files
(such as database server software). Such applica- tions tend to
perform better with a smaller block size, although modern disk
characteristics are such that the performance gain from using a
smaller block size may not be worth consideration. Using a
block size larger than 16K can cause fragmentation of the buffer
cache and lead to lower performance.
The defaults may be unsuitable for a file system that
requires a very large number of i-nodes or is intended to hold a
large number of very small files. Such a file system should be
created with an 8K or 4K block size. This also requires you to
specify a smaller fragment size. We recommend always using a
fragment size that is 1/8 the block size (less testing has been
done on other fragment size factors).
Reading this makes me think that when this server was installed,
the block size was dropped from the 16K default to 8K for
performance reasons, but the fragment size was not modified
accordingly.
Would this be the root of my problem? If so, is my only option
to back everything up and newfs the disk, or is there something
else I can do that will minimise my downtime?
Any help and advice would be greatly appreciated.
-Feargal.
--=20
Feargal Reilly, Chief Techie, FBI.
PGP Key: 0x105D7168 (expires: 2006-11-30)
Web: http://www.fbi.ie/ | Tel: +353.14988588 | Fax: +353.14988489
Communications House, 11 Sallymount Avenue, Ranelagh, Dublin 6.
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