I had a few queries recently on how Virtual Volumes (VVols) worked with vSphere HA. In particular, I had a number of questions around whether or not VVol datastores could be used as a heartbeat datastore by vSphere HA. The answer is yes, the VVol datastore can be used for vSphere HA datastore heartbeating. If you want to see how, please read on. I think these queries may have arisen due to the fact that we do not use datastore heartbeating with Virtual SAN (VSAN). Just by way of reminder, the master host in a vSphere HA cluster uses a…
I’ve been hit up this week by a number of folks asking about “ATS Miscompare detected between test and set HB images” messages after upgrading to vSphere 5.5U2 and 6.0. The purpose of this post is to give you some background on why this might have started to happen. First off, ATS is the Atomic Test and Set primitive which is one of the VAAI primitives. You can read all about VAAI primitives in the white paper. HB is short for heartbeat. This is how ownership of a file (e.g VMDK) is maintained on VMFS, i.e. lock. You can read…