It should still be part of the added HAE pack for SLES.
Our clustered Xen setups run on plain SLES though (no HAE), the DomUs/VMs get thier OS disk on a shared LVM VG volume. Locking on the Xen hosts ensures a guest does not get started multiple times and we have some small scripts that run every couple of minutes that keep configurations across hosts updated.
Main reason for the LVM approach for the OS disk, even if LVM is not cluster aware… is the added functionality of LVM snapshots (makes scripted dumps of domU OS disks quite an easy task while keeping downtime -if needed- to a minimum).
But it must be stressed that this requires knowlegde of correct setup and workings or one might end up with corrupt metadata.
The data disks for the DomUs/VMs are raw iSCSI devices that get passed on through the Xen host to the DomU/VMs.
As central management we are using Convirt, as it also keeps track of who’s running what and it greatly simplifies administration as it’s web based. (Look here for a quick start http://susestudio.com/a/YtQGNq/sles11sp2-convirt-xen-kvm)
So yes, it can be done and done well. Care must be taken in doing it correctly