FreeBSD8.1 AMD64 UFS2 file system size issues.

Matthew Seaman m.seaman at
Sun Sep 5 07:54:13 UTC 2010

On 04/09/2010 20:35:02, troy at wrote:

> I am having a problem with a fresh install onto a    that is 9TB in
> size. during the initial install, the syste   the correct disk size
> and partition sizes, but after it has complete   d and rebooted it
> shows the the large partition as only 1TB. I am using a 3w   message,
> it shows that    On initial install, this is   Total disk size: Sep
> 4 12:17:51 fi   (19531038720 512 byte sectors: 255H 63S/T 1215   1G
> da0s1a     /&nbs   4G     da0s1b  &nb   2G     da0s1d     36G
> da0s1e &n   remainder da0s1f &nbs   Upon completion of insta   up as
> this: Filesystem&nbs   on /dev/da0s1a    1012974  2   devfs
> /dev/da0s1f 1094909108       4 10   /dev/da0s1e&nb   /dev/da0s1d
> 2026030  &n   It was my understanding that UFS2 supports drive s
> what I am trying to use. Is there something that I am doing
> Thanks,

Weird.  Something seems to have eaten chunks out of your message.  I
suspect a less than optimal conversion from HTML -- for best results
write to FreeBSD lists in plain text.

Anyhow, you've got a system with 9TB disk but your big partition gets

It's not the limits in the UFS2 filesystem that are biting you: that can
handle individual files of up to 32 PB (with the right options) and a
total filesystem size of 1 YB.  You may not be familiar with Y 'Yotta'
as an SI prefix: it means 10^24.  That's more than enough to boil the
oceans should you attempt to create a filesystem of that size[*].

I suspect that you are running into limitations of the disk label.  The
original Dos-derived MBR that you can manipulate with fdisk(8) is based
around 32bit quantities and has an inherent limitation to 2TB per
partition.  There are ways around this, not least by using the new
gpart(8) disk partitioning.  See:

Personally, I'd start again from scratch and install using both gpart(8)
and zfs(1M).  Unfortunately sysinstall(8) can't handle doing that at the
moment.  You need to follow a different procedure described here:  (Or the equivalent
pages for RAIDZ1 or RAIDZ2 if that's what you prefer)

Although ZFS's maximum size is /only/ 1 EB (individual file or whole
filesystem) it should still suffice.  The compelling advantage with ZFS
is the built-in checksumming of every data block.  That's important for
large data volumes where bitwise errors can become significant.  Also,
no need for fsck(8).  Not even background fsck.



[*] Kids: don't try this at home.

Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP:     Ramsgate
JID: matthew at               Kent, CT11 9PW

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