Re: UFS2 filesystem and filesize limits

From: Kenneth D. Merry <ken_at_freebsd.org>
Date: Fri, 2 Jul 2004 13:23:35 -0600
On Fri, Jul 02, 2004 at 10:37:59 -0600, Kenneth D. Merry wrote:
> 
> I've searched a bit on the list archives, but didn't find an obvious answer
> so I thought I'd ask:
> 
> What is the maximum possible size of a UFS2 filesystem?  Are there any
> gotchas associated with going that large?
> 
> What is the maximum possible file size on a UFS2 filesystem?

Evidently there are some limits.  I can create a 11TB filesystem, but I can
only put 714GB or so on it:

# dd if=/dev/zero of=bigfile bs=1m

/bigdisk: write failed, filesystem is full
dd: bigfile: No space left on device
730368+0 records in
730367+0 records out
765845307392 bytes transferred in 11211.369691 secs (68309701 bytes/sec)
# ls
.snap/          bigfile
# ls -la
total 748261206
drwxr-xr-x   3 root  wheel              512 Jul  2 10:02 ./
drwxr-xr-x  21 root  wheel              512 Jul  2 09:43 ../
drwxrwxr-x   2 root  operator           512 Jul  2 09:39 .snap/
-rw-------   1 root  wheel     765845307392 Jul  2 13:09 bigfile
# dd if=/dev/zero of=bigfile.2 bs=1m

/bigdisk: write failed, filesystem is full
dd: bigfile.2: No space left on device
257+0 records in
256+0 records out
268435456 bytes transferred in 3.409144 secs (78739843 bytes/sec)
# df
Filesystem  1K-blocks        Used      Avail Capacity  Mounted on
/dev/da0s1a      507630    186246     280774    40%    /
devfs                 1         1          0   100%    /dev
/dev/da0s1e    31515362   1301220   27692914     4%    /usr
/dev/da0s1d      507630      3470     463550     1%    /var
/dev/ccd0   11349755298 748523524 9693251352     7%    /bigdisk
# dd if=/dev/zero of=bigfile.3 bs=1m

/bigdisk: write failed, filesystem is full
dd: bigfile.3: No space left on device
33+0 records in
32+0 records out
33554432 bytes transferred in 0.319315 secs (105082557 bytes/sec)
# df -h
Filesystem     Size    Used   Avail Capacity  Mounted on
/dev/da0s1a    496M    182M    274M    40%    /
devfs          1.0K    1.0K      0B   100%    /dev
/dev/da0s1e     30G    1.2G     26G     4%    /usr
/dev/da0s1d    496M    3.4M    453M     1%    /var
/dev/ccd0       11T    714G    9.0T     7%    /bigdisk

Ken
-- 
Kenneth Merry
ken_at_FreeBSD.ORG
Received on Fri Jul 02 2004 - 17:26:21 UTC

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