[zfs-discuss] One dataset per user?

David Magda
2010-06-20T16:27:56Z

On Jun 20, 2010, at 11:55, Roy Sigurd Karlsbakk wrote:

> There will also be a few common areas for each department and
> perhaps a backup area.

The back up area should be on a different set of disks.

IMHO, a back up isn''t a back up unless it is an /independent/ copy of
the data. The copy can be made via ZFS send/recv, tar, rsync, Legato/
NetBackup, etc., but it needs to be on independent media. Otherwise,
if the original copy goes, so does the "backup".

> I have read people are having problems with lengthy boot times with
> lots of datasets. We''re planning to do extensive snapshotting on
> this system, so there might be close to a hundred snapshots per
> dataset, perhaps more. With 200 users and perhaps 10-20 shared
> department datasets, the number of filesystems, snapshots included,
> will be around 20k or more.

You may also want to consider breaking things up into different pools
as well. There seems to be an implicit assumption in this conversation
that everything will be in one pool, and that may not be the best
course of action.

Perhaps one pool for users'' homedirs, and another for the departmental
stuff? Or perhaps even two different pools for homedirs, with users
''randomly'' distributed between the two (though definitely
don''t do
something like alphabetical (it''ll be non-even) or departmental
(people transfer) distribution).

This could add a bit of overhead, but I don''t think have 2 or 3 pools
would be much more of a big deal than one.