People will do whatever they want to do. And my comment is not a knock on HAST. But myself, and I know I am not alone, firmly believe especially regarding HA a

People will do whatever they want to do. And my comment is not a knock on HAST. But myself, and I know I am not alone, firmly believe especially regarding HA and ZFS that following anything other than the KISS principle is pain upon pain upon pain. Wether it's iSCSI, HAST, NFS, HAST or any combination thereof. The simplest and least painful? Is to simply create two servers with dual nic's and dual HBA's. Assign half the disks in a mirror to HBA-1 the other half to HBA-2. Use one nic for public networking, use the other for a direct P2P Gig-E link between server A and server B. Use zfs replication over the private network link using the granularity you feel most comfortable with. 30 minutes? 15 minutes? 5? It's up to you. This is the simplest, and IMO most reliable way to go about this. When you start adding in iSCSI, NFS, HAST etc you are simply making things to complex, introducing multiple points of failure, and the pain when something does break? Ill pass. I'd rather have to manually intervene and fail over to server B if server A fails and vice versa than deal with all the pain of additional things that could break or introduce split brained issues etc. But it's a free world, use whatever solution fits your comfort zone.