[Xen-users] UnionFS + Xen

["Gino LV. Ledesma" <gledesma@xxxxxxxxx>]

Hi, list

I've been looking at solutions to copy UML's CoW disks for Xen, but
based on the archives and google results, this is pretty much an
active work-in-progress for Xen. I've looked at CowNFS and it seems
promising, but I'm a bit worried of relying on a machine that will run
it. If and when the daemon conks out, everything relying on it will
die as well (can't get the clients to reestablish a connection with
the server).

What I've been looking at lately is using NFS Root + UnionFS. Having
NFS root means I can use a dedicated machine to act as an NFS server
and tweak it to my heart's content, or maybe even use a NetApp for it.

The only challenge this poses is getting the guest OSs to actually do
the overlaying by mounting a copy of their work space (read/write)
over the exported NFS root (read-only). This way, each domain can
happily write to their own "disk" without having to give them their
own independent disks (which wastes space).

Has anyone gotten something similar to work? Any ideas / tips /
comments / suggestions in doing so? I'm tweaking my xen RPM spec file
to support unionfs and right now just looking at the boot up process
of getting the domain to mount something else on top of the exported
root file system (either a file-backed VBD or yet another NFS export).

gino ledesma

P.S. If there's anything waaaay simpler than this, I'd really like to
know. :-) I'm having fun playing with xen but will need to see how
this setup scales.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users