We recently moved back to a physical commserve for a number of reasons,
1. CommServe eventually had 4 Cores and 16Gb of RAM assigned and was consistantly in the top 5 VMs in terms of CPU/RAM/Disk activity.
2. We looked at our DR situation, and as our virtual center was virtualised as well and we realised that, in order to get our environment back from a total disaster we needed 4 things before we could start to perform restores for a lot of critical systems.
A. VMWare environment restored.
B. SQL Cluster restores (it holds the Virtual Center DB)
C. Virtual Center Restored.
D. Commserve restored.
All of these kind of depend on each other in our environment and DR was a little clunky in terms of what we did first, now there are workarounds but by taking the commserve back to a physical we eliminated some of the catch-22 situations that we faced, and improved our RTO massively.
Before virtualising your commserve, I would recommend that you look at each element of your environemnt and ask yourself "What impact would a virtual commserve have if we lost this?".