Thoughts on Quotas

[Michael Neumann]

Hi,

What do people think about qutoas in general? Are they really useful? I
know there is a GSoC proposal for a generic quota API, but would that be
really useful for HAMMER with it's fine grained snapshots? I mean, would
the historical data be accounted for that user as well or not?

And then, I don't think quotas would be widely used on anything other
than a HAMMER filesystem, so that I would not mind to see a HAMMER-only
quota solution. 

My usage scenario is a Fileserver with many users. One thing that comes
to mind is to spend one PFS per user home directory. IIRC, HAMMER
supports up to 2^16 PFS. In my case it is obvious that limiting the real
diskspace used by each PFS would be a nice feature, not only in my case,
but also imagine one PFS per vkernel or jail, which would give much
stronger separation guaratees than what we have right now.

I am probably putting this question towards Matt because he knows best
about HAMMER... so how hard would it be to implement (soft) PFS disk
space tracking and limitation?

Regards,

  Michael