ZFS user/group quotas & space accounting [PSARC/2009/204 FastTrack timeout 04/08/2009]

[Darren Reed]

Matthew Ahrens wrote:
> ...
> User space accounting and quotas "stick with" each dataset (snapshot,
> filesystem, and clone).  This means that user quotas (and space
> accounting) are not inherited.  They will be "copied" to a new snapshot,
> and keep the values they had at the time the snapshot was taken.
> Likewise, user quotas will be "copied" to a clone (from its origin
> snapshot), and they will be copied with "zfs send" (even without -R).
> (User accounting and quota information is not actually copied to
> snapshots and clones, just referenced and copied-on-write like other
> filesystem contents.)

If I read this right then the implication is that a user can use
snapshot/clone to increase their allotted quota in a givern pool
because they can create more datasets with their own quota, correct?

So if I start out with tank/test1 that has a quota of 2GB, create a
snapshot of that (tank/test1 at now) and then clone it (test/test1_clone),
I end up with 4GB of quota for tank/test1. That's different.

If at some point in the future there was a desire to implement quotas
for pools, does anything this project delivers make that "impossible"?

Darren