[OpenIndiana-discuss] convert some directories to shared dataset?

[Tim Mooney]

All-

Is it possible to convert some directories in an existing OI install,
that are currently part of the "critical datasets" that get snapshotted
and are part of each boot environment, to be shared datasets and not
be included in the boot environment?  I'm specifically thinking about
/var/tmp, but /var/mail would be another place I would consider.

When I installed my OI workstation, I only had basic familiarity with
ZFS and I knew next to nothing about boot environments.  At the time, I
thought it was "advanced" to use the text installer to set up a mirrored
rpool and then do the install on that.

The enterprise backup software that my workplace uses automatically skips
backing up anything in /tmp, /var/tmp, or /usr/tmp.  That behavior is
so familiar to me that over the years I've picked up a bad habit of
stashing stuff in /var/tmp that I might need again, but that doesn't
need to be backed up.  Stuff like ISO images, BIOS update packages for
various servers I manage, etc.

People that saw my mailing list posts from this weekend, about a nearly
full rpool, know where this story is going.  I should have realized that
*all of /var, including /var/tmp* is treated as part of the boot
environment, so any junk I leave in /var/tmp gets added to the ZFS clone
for the boot environment.

Obviously I need to break the habit of using /var/tmp on my workstation
as my own ISO cache.  Still, it's always been an annoyance that /var/mail
is part of the boot environment.  In one case in the past when I ended
up reverting to an older boot environment, I ended up losing a little
mail that had been delivered to the newer boot env while it was active.
Now I'm in the habit of shutting down sendmail before I pkg update, but
it still seems kind of pointless to include /var/mail in the snapshot.

I remember seeing a patch years ago that made the install move some
parts (?) of /var outside the boot environment, but that was install-time
only and it was never incorporated into the installer.

So, is there a way to convert /var/tmp or /var/mail or potentially other
spots in /var on an existing install so that they are not included in the
boot environment?

Thanks,

Tim
-- 
Tim Mooney                                             Tim.Mooney at ndsu.edu
Enterprise Computing & Infrastructure /
Division of Information Technology    /                701-231-1076 (Voice)
North Dakota State University, Fargo, ND 58105-5164