* Re: Inodes disappearing
2007-02-09 12:49 Inodes disappearing Jan Engelhardt
@ 2007-02-09 15:07 ` Eric Sandeen
0 siblings, 0 replies; 2+ messages in thread
From: Eric Sandeen @ 2007-02-09 15:07 UTC (permalink / raw)
To: Jan Engelhardt; +Cc: xfs
Jan Engelhardt wrote:
> Hello list,
>
>
> here's an interesting phenomena I am seeing:
>
> # df -h
> /dev/hda3 215G 152G 63G 71% /sam224
> /dev/dm-0 233G 233G 350M 100% /sam250
> # df -i
> Filesystem Inodes IUsed IFree IUse% Mounted on
> /dev/hda3 112254144 33076 112221068 1% /sam224
> /dev/dm-0 1466272 35982 1430290 3% /sam250
>
> How come that dm-0 has much less inodes despite the two volumes having
> about the same size? It can't be because of isize=512, can it? (If at
> all, I would expect an isize=512 volume to have less inodes than a
> isize=256 one for the same number of blocks.)
xfs dynamically allocates inodes, up to a maximum percentage of disk
space specified at mkfs time, changeable by growfs. By default this is
25%, and from output below that's what you have. So the total inodes
number from df is given by taking 25% of your data space, and
calculating how many inodes would fit into that space.
Since your filesystems are roughly the same size, that means you started
out with roughly the same amount of space available for inodes in each.
dm-0 has 256-byte inodes, hda3 has 512-byte inodes, which means for a
given amount of space, you -can- fit more (256-byte) inodes into the
filesystem on dm-0.
However, dm-0 is completely full, and there is very little space left
for at all. If you look at xfs_statvfs(); you'll see all these
calculations that go into your answers above.
inodes which -could- be created based on free space:
fakeinos = statp->f_bfree << sbp->sb_inopblog;
total inodes is min of (current + possible) and max inode nr:
statp->f_files =
MIN(sbp->sb_icount + fakeinos, (__uint64_t)XFS_MAXINUMBER);
... which is then limited by the configured max percentage:
if (mp->m_maxicount)
....
statp->f_files = min_t(typeof(statp->f_files),
statp->f_files,
mp->m_maxicount);
your free blocks is low, so you start with a low number for "fakeinos"
and your final result reflects that. You've used most of your potential
inode space for data.
-Eric
>
> # xfs_info /dev/dm-0
> meta-data=/dev/disk/by-label/sam250 isize=256 agcount=16, agsize=3813429 blks = sectsz=512 attr=0
> data = bsize=4096 blocks=61014864, imaxpct=25
> = sunit=0 swidth=0 blks, unwritten=1
> naming =version 2 bsize=4096
> log =internal bsize=4096 blocks=29792, version=1
> = sectsz=512 sunit=0 blks
> realtime =none extsz=65536 blocks=0, rtextents=0
>
> # xfs_info /dev/hda3
> meta-data=/dev/disk/by-label/sam224 isize=512 agcount=16, agsize=3507943 blks = sectsz=512 attr=0
> data = bsize=4096 blocks=56127088, imaxpct=25
> = sunit=0 swidth=0 blks, unwritten=1
> naming =version 2 bsize=4096
> log =internal bsize=4096 blocks=27405, version=1
> = sectsz=512 sunit=0 blks
> realtime =none extsz=65536 blocks=0, rtextents=0
>
>
> Jan
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