On Sun, Sep 16, 2012 at 7:43 PM, Edward Ned Harvey
> There's another lesson to be learned here.
> As mentioned by Matthew, you can tweak your reservation (or refreservation)
> on the zvol, but you do so at your own risk, possibly putting yourself into a
> situation where writes to the zvol might get denied.
> But the important implied meaning is the converse - If you have guest VM's in
> the filesystem (for example, if you're sharing NFS to ESX, or if you're
> running VirtualBox) then you might want to set the reservation (or
> refreservation) for those filesystems modeled after the zvol behavior. In
> other words, you might want to guarantee that ESX or VirtualBox can always
> write. It's probably a smart thing to do, in a lot of situations.
I'd say just do what you normally do.
In my case, I use sparse files or dynamic disk images anyway, so when
I use zvols I use "zfs create -s". That single switch sets reservation
and refreservation to "none",
zfs-discuss mailing list