Clustered file systems as XenServer storage

I want to use shared storage for a XenServer environment with 4 host servers which are running various VMs under XenServer. Planning to use 2 extra servers as storage with high availability of some sort.

While the most obvious solution is iSCSI SAN software, I see some recommendations that one skip iSCSI altogether and go for clustered file systems – most prominent seem GFS2 and Lustre.

However, I don’t see options in XenServer which support connecting to such clustered systems.

First of all, do I need to then make the 4 XenServer hosts also part of the cluster? As I am installing via the Citrix download, I am not familiar how I would go about it, or if I even need to.

Don’t need more than 30 VMs and storage is limited below 4 TB. Under these circumstances, what cluster type is best? Or does this not work at all with Xen?