On Sun, Sep 26, 2010 at 8:56 AM, Justin C. Sherrill <[email protected]> wrote: > On Sun, September 26, 2010 8:32 am, Michael Neumann wrote: > >> 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. > > The one thing that comes immediately to mind is scale. Usually, a > DragonFly system has less than 10 PFSs. (What's the plural of PFS?) > /home, /var, /usr, etc. Having a per-user PFS setup seems appealing > because then you can set up snapshot and mirroring properties on a > per-user basis. > > However, what happens where there's 200 users on a machine? It would be > very frustrating to keep track of the settings of each user and to > implement changes on each, especially if some users get different settings > than others. I think the user->PFS idea is good; it just may require a > different set of tools. > >
2^16 is nowhere close to enough. Quota's are very useful and to be useful you need to support hundreds of thousands of users. I consider lack of useful quota's to be one of our most major deficiencies. If a person wanted to do accounting of space usage of the historical data for snapshots, that could be done too with a userland tool by hooking into the mirror-stream ioctl's (I don't know what indication there is of free'd space, but I assume something could be worked out), but I don't see that as falling under the same umbrella as quota's necessarily. Sam
