I find a lot of advertisement on iscsi and vsphere support but nowhere do I find anything about high-availalbity clusters. How come? In order to seriously use Synology NAS for virtualization as iscsi hosts, automatic (block-level) synchronization of at least 2 Synology NASes is absolutely required. I cannot see that anybody would voluntarily have all his/her virtual machines run from only one NAS and upon bad luck with this single point of failure all instances would be lost.
The requirements for a typical SME KVM or Xen setup are high availability, low cost, simple configuration and performance. To have several virtual machine hosts that can dynamically run different virtual instances is fairly straight forward and redundancy is easily obtained. To obtain redundancy on the storage side is not as straight forward at all. Classically DRBD and a daemon like, i.e., Heartbeat are employed to also remove the single point of failure on the storage side.
I could see a wonderful rig-up for Synology here: Suitable Synology NASes already do have at least 2 NICs, so one NIC could be used for DRBD synchronization and Heartbeat. A configuration wizard that configures the block-level synchronization and Synology would sell two units to all HA-seeking SMEs that want to run KVM or Xen without SAN.
In fact this would be a wonderful app for power users. I can see that DRBD would conflict with many of the other higher level configuration programs of DSM, but this would be readily accepted by the power users seeking HA.
Anybody else thinks like I do? Anybody else found a Synology-based HA solution?