system/bootenv/default/var does not contain /var

Much like the system/bootenv/default/usr does not contain /usr issue I recently wrote about, I found the same issue with system/bootenv/default/var

For this post, I have booted my FreeBSD 9.3 system from mfsBSD thumb drive.

I will import the pool, but not mount it.

# zpool import -N system

I mounted the filesystem in question, and confirm that there is just one ZFS thing mounted:

# mount -t zfs system/bootenv/default/var /mnt
# mount -t zfs system/bootenv/default/var /mnt
root@mfsbsd:~ # zfs mount
system/bootenv/default/var      /mnt

Let’s look in there:

# cd /mnt
# ls -l
total 0
# ls -lat
total 18
drwxr-xr-x  18 root  wheel  512 Mar 13 19:07 ..
drwxr-xr-x   2 root  wheel    2 May  3  2013 .
# zfs

Nothing in there. Let’s look at system/bootenv/default:

# cd
# umount /mnt
# mount -t zfs system/bootenv/default /mnt
# cd /mnt
# ls -lat
total 391
drwxr-xr-x  18 root  wheel   512 Mar 13 19:07 ..
-rw-------   1 root  wheel  4096 Mar 13 19:02 entropy
drwxr-xr-x  22 root  wheel    28 Mar 13 19:02 .
drwxr-xr-x  22 root  wheel   149 Mar 12 18:13 etc
drwxr-xr-x  26 root  wheel    26 Mar 12 18:13 var
drwxr-xr-x  17 root  wheel    17 Mar 11 21:44 usr
drwxr-xr-x   8 root  wheel    44 Mar  9 02:10 boot
drwxr-xr-x   2 root  wheel     2 Mar  9 00:37 data
drwxr-xr-x   2 root  wheel     2 Mar  8 23:56 tmp
drwxr-xr-x   2 root  wheel   144 Feb 25 21:52 rescue
drwxr-xr-x   3 root  wheel    49 Feb 25 21:52 lib
drwxr-xr-x   2 root  wheel     2 Dec 25 15:27 ssd
drwxr-xr-x   2 root  wheel   132 Oct 26 14:50 sbin
drwxr-xr-x   3 root  wheel     4 Aug 11  2014 libexec
drwxr-xr-x   2 root  wheel    46 Aug 11  2014 bin
-r--r--r--   1 root  wheel  6197 Aug 11  2014 COPYRIGHT
-rw-r--r--   1 root  wheel   253 Aug 11  2014 .profile
-rw-r--r--   1 root  wheel   965 Aug 11  2014 .cshrc
drwxr-xr-x   2 root  wheel     2 May  2  2014 backups
drwxr-xr-x   2 root  wheel     2 Sep  9  2013 mnt
lrwxr-xr-x   1 root  wheel     8 May  3  2013 home -> usr/home
lrwxr-xr-x   1 root  wheel    11 Dec  4  2012 sys -> usr/src/sys
drwxr-xr-x   2 root  wheel     6 Dec  4  2012 root
dr-xr-xr-x   2 root  wheel     2 Dec  4  2012 dev
drwxr-xr-x   2 root  wheel     2 Dec  4  2012 media
dr-xr-xr-x   2 root  wheel     2 Dec  4  2012 proc
#

Yes, there’s /var. How big is it?

# du -ch -d 1 var
692M	var/cache
 17K	var/account
 59K	var/cron
 17K	var/rwho
284K	var/run
1.8M	var/spool
 17K	var/authpf
 17K	var/preserve
188M	var/named
 17K	var/empty
 33K	var/lib
 17K	var/games
 66K	var/munin
 50K	var/at
 17K	var/audit
 22K	var/mail
 33K	var/tmp
 51M	var/backups
 25K	var/msgs
 50K	var/yp
 25K	var/crash
 17K	var/heimdal
2.7G	var/db
 17K	var/log
3.6G	var
3.6G	total

That var/db is big. What’s in there?

# du -ch -d 1 var/db
797M	var/db/mysql
105M	var/db/pkg
4.7M	var/db/etcupdate
1.3M	var/db/ports
284M	var/db/portsnap
 25K	var/db/postfix
 59K	var/db/logcheck
 34K	var/db/bacula
1.4G	var/db/freebsd-update
203K	var/db/sudo
230K	var/db/fontconfig
 17K	var/db/ipf
 85K	var/db/entropy
2.7G	var/db
2.7G	total

That looks sane.

OK, let’s do this

This will copy things over:

tar clf - -C /mnt/var . | tar xpvf - -C /DEST/

After the copy, we have:

# cd /DEST
# ls -l
total 396
drwxr-xr-x   2 root    wheel    2 Dec  4  2012 account
drwxr-xr-x   4 root    wheel    4 Dec  4  2012 at
drwxr-xr-x   2 root    wheel    2 Mar  8 23:56 audit
drwxrwx---   2 root    authpf   2 Nov  8  2013 authpf
drwxr-x---   2 root    wheel   13 Mar 13 05:17 backups
drwxr-xr-x   3 root    wheel    3 Nov 14  2013 cache
drwxr-x---   2 root    wheel    3 Dec  4  2012 crash
drwxr-x---   3 root    wheel    3 Dec  4  2012 cron
drwxr-xr-x  15 root    wheel   20 Mar 13 16:02 db
dr-xr-xr-x   2 root    wheel    2 Dec  4  2012 empty
drwxrwxr-x   2 root    games    2 Dec  4  2012 games
drwx------   2 root    wheel    2 Dec  4  2012 heimdal
drwxr-xr-x   3 root    wheel    3 Jun 10  2014 lib
drwxr-xr-x   2 root    wheel    3 Dec  4  2012 log
drwxrwxr-x   2 root    mail    13 Feb 24 18:17 mail
drwxr-xr-x   2 daemon  wheel    3 May  3  2013 msgs
drwxr-xr-x   3 842     842      3 Jun 10  2014 munin
drwxr-xr-x   6 root    wheel    6 Jun  5  2013 named
drwxr-xr-x   2 root    wheel    2 Dec  4  2012 preserve
drwxr-xr-x  10 root    wheel   19 Mar 13 16:02 run
drwxrwxr-x   2 root    daemon   2 Dec  4  2012 rwho
drwxr-xr-x  11 root    wheel   11 Dec  9 20:09 spool
drwxrwxrwt   3 root    wheel    3 Dec  4  2012 tmp
drwxr-xr-x   2 root    wheel    4 Aug 11  2014 yp
#

Note that /DEST does not contain a /var. That is because our mountpoint is /var and I can prove that with this:

# zfs mount
system/bootenv/default          /mnt
system/bootenv/default/var      /DEST

# zfs get mountpoint system/bootenv/default/var
NAME                        PROPERTY    VALUE       SOURCE
system/bootenv/default/var  mountpoint  /var        inherited from system/bootenv/default

Rename the old var

I renamed the old /span class=”file”>/var directory on the system/bootenv/default dataset:

# cd /mnt
# mv var zzz-DELETE-me-OLD-var

This allows me to keep the old /var. I’m pretty sure the old /var would be overwritten by the new /var when it was mounted from system/bootenv/default/var, but renaming allows:

Proof that the old /var is not mounted.
Reminds me to delete the old /var later.
Keeps the old /var accessible should I want to grab something from it.

This is the important bit

Do not forget this:

zfs set canmount=yes system/bootenv/default/var

Thoughts

I have been thinking that it might be better to not do what I’ve been doing. That it’s better to have the top level mountpoint be empty. Time will tell.

Reboot time.