> sanlock is designed to be used on a shared block device
directly.
> Using it on top of gfs2 doesn't make much sense.
>
>
That's how libvirtd implements it (
http://libvirt.org/locking.html). It
expects a directory configured by the disk_lease_dir parameter, not a block
device.
It should probably gain the ability to use block devices.
I don't see why NFS would make more sense than GFS2, since NFS
also exports
a directory?
The main reason to use sanlock is in cases where you don't have clustering
capabilites to do locking/coordination more directly.
libvirt could also gain the ability to use the cluster/locking
capabilities of gfs2 directly, e.g. it could just take an flock on the
file.