Russell Coker <russell@coker.com.au> writes:
2) Use NFS to mount a ZFS filesystem from the Dom0. This will be good for management but there's the problem of caching. I don't think that NFS caches that aggressively so I'd need to give more RAM to the Dom0 for ZFS caching and I'd probably still lose some read performance.
$coworker was smoking more crack than usual recently, and he suggested we try p9 instead of NFS. There's a userland server and a in-kernel client. Access control is normal DAC -- p9 server just accesses files as the user it was run as. I assume there's some kind of SSH-style crypto handshake to then allow the client to talk to the server; I didn't look. Anyway, in your case in the dom0 you'd create a mail user, sudo -u mail p9thingo /srv/mail, then have the domU mount it. And probably a firewall to ensure the bound port isn't visible to the rest of the world. If you are crazy enough to try it, do let me know how it turns out :-) Oh, and if you do go NFSv3, don't forget to do the usual things like cranking the read/write blocks up and telling portmapper to assign fixed ports. Of course, maildir is about the worst thing to on NFS, short of perhaps tar x.