[libvirt-users] best shared storage solution ?

[Jason Vas Dias]

Good day -
Is there a way of safely allowing a guest OS to access a disk storage device
that is also mounted at the same time by the hypervisor or another guest ?
I have Linux LVM volumes containing ext4 and btrfs filestystems
that need to be shared between the hypervisor and the guests, and
between guests .

Attempts to use NFS are too slow to be useable - it takes a guest around
4 hours to  uncompress and extract a 10MB tar file (using 4 2.9GHz cores).

I need access to the shared file system at all times to use as my /home
directory from the hypervisor host, so I guess this rules out iSCSI .

I came accross documentation on 'sanlock', but its purpose seems to be
antithetical to what I require, as described at:
http://libvirt.org/locking.html :
" how to ensure a single disk cannot be used by more than one running
VM at a time, across any host in a network" - but I want to ensure
SAFE
concurrent access by multiple VMs or any kernel , either on the
hypervisor hardware or in a  VM guest,  to the same filesystems (
ext4, btrfs ) on the
same machine, without having to use a network file system .

Can sanlock be used to accomplish this ?
Or is there any other method that allows the same filesystem to be safely
accessed by more than one kernel running on the same host ?

The libvirt documentation is very sketchy on this subject, but I understand
that just using the '<shareable/>' in the VM configuration XML is not enough,
and a lock manager must be configured - can sanlock be used for this, or
is there another lock manager that can ?

Thanks & Regards,
Jason Vas Dias