zfs home directories best practice

[Rick Macklem]

Graham Allan wrote:
> On 4/3/2013 6:56 PM, Rick Macklem wrote:
> >>
> > Well, there isn't any limit to the # of exported file systems afaik,
> > but updating a large /etc/exports file takes quite a bit of time and
> > when you use mountd (the default) for this, you can have problems.
> > (You either have a period of time when no client can get response
> >   from the server or a period of time when I/O fails because the
> >   file system isn't re-exported yet.)
> >
> > If you choose this approach, you should look seriously at using
> > nfse (on sourceforge) instead of mountd.
> 
> That's an interesting-looking project though I'm beginning to think
> that
> unless there's some serious downside to the "one big filesystem", I
> should just defer the per-user filesystems for the system after this
> one. As you remind me below, I'll probably have other issues to chase
> down besides that one (performance as well as making the jump to
> NFSv4...)
> 
> > You might also want to contact Garrett Wollman w.r.t. the NFS
> > server patch(es) and setup he is using, since he has been
> > working through performance issues (relatively successfully
> > now, as I understand) for a fairly large NFS/ZFS server.
> > You should be able to find a thread discussing this on
> > freebsd-fs or freebsd-current.
> 
> I found the thread "NFS server bottlenecks" on freebsd-hackers, which
> has a lot of interesting reading, and then also "NFS DRC size" on
> freebsd-fs. We might dig into some of that material (eg DRC-related
> patches) though I probably need to spend more time on basics first
> (kernel parameters, number of nfsd threads, etc).
> 
Hopefully I can get to-gether with ivoras@ in May and come up with a
patch for head/current. If you want to try something before then, this
patch is roughly what Garrett is using:
  http://people.freebsd.org/~rmacklem/drc4.patch

rick

> Thanks for the pointers,
> 
> Graham
> --