We're going to host a large SQL Server 2012 under a VMware virtualization and we need it to be highly available.

These are the three options I found supported, but couldn't find a lot of info and comparison on who's better and why (and mostly - what's the disadvantages):

  1. VMware HA - pro: cheap and easy to use and configure, just let the VM team deal with it. con: no HA for system upgrades, e.g. SQL upgrades, Windows services-packs\KBs etc.
  2. SQL Server Failover Cluster (FCS) - pro: well known, supported, saves space (compared to AlwaysOn Availability Group), HA for system upgrades. con: I haven't heard of successful clusters over VM, or at least good ones. Heard it's a mess and to "stay away from it". A bit harder to admin, some problems may take days to figure out (no-one with a lot of knowledge).
  3. SQL Server AlwaysOn Availability Group - pro: HA for everything! system, DB etc. con: New, added administering and hard to confiugre, new problems to deal with, double the space(!), "no strings attached" (to other servers).

That's pretty much it.

I would appreciate any info you may have about this, and would appreciate even more recommendations (hopefully based on test cases).