I am looking at upgrading our current VI to vSphere and take advantage of FT for our web application server... I am curious though... as the machines run in lockstep, would the secondary VM be performing the same I/O on the backend database? What would happen there... ?
Hello.
Only the primary VM would do the I/O on the backend database. The secondary VM would only start issuing I/O in the event of a failure of the primary VM. Check out kb 1010601 and kb 1013428 for more info on how FT works.
Good Luck!
vmroyale is right, but here's another way to think about it. The secondary VM is issuing IOs, but they are being caught by the hypervisor and dropped on the floor, in favor of the primary VM.
--Matt
VCP, vExpert, Unix Geek