The only SAS server we have tested in an HA environment is the Metadata Server. If those are the two choices, the active/passive is what I would say we are. This is done with 3rd party HA tools from the various UNIX operating systems. Please note that we can get the OMR server's downtime to being very slight, but it will never be 0. Also, I believe that any transactions/updates/modifications that happen while the OMR is down are not captured by any tool. These will have to be redone.