I’m after viewpoints on my situation from my fellow sysadmins. I think I have thought of the points, but want someone else’s opinion.
I have an ESXi5 Cluster consisting of 5 Physical machines: 4 in DRS Pool and 1 spare for DR. Nothing sits on this in case we need to Vmotion to spread the load during a spike we can. It's also quite handy for maintenance windows.
We have a Database server that is starting to getting more use as the business grows (A good thing!). It is gotten to the point now where I want to take the Database server out of the cluster and move it to its own separate physical hardware, because I can't give it enough virtualized resources currently. I’m of two minds whether to install ESXi onto this, as the ESXi Hypervisor has very little overhead and then I can add this machine as part of our cluster so should anything go wrong we still have another server to back this up.
On the other hand, I am thinking I could just install Windows 2008R2 and use a MSSQL Database to host this on its own as over time I think we may go down the route of database replication. There will be no local storage as this is all SAN based.
Can anyone foresee any problems with hosting this as a virtual host?
Edit I have accepted Jeremy’s Answer as this has provoked some of my thoughts and has led me to a solution. I will be keeping this as a VM below is what I plan to do. I will be adding another ~100GB RAM into 2 of our Servers, so in case one fails there is still enough resources in the cluster. I will be setting DRS to apply affinity’s to this and allow for more vCPU’s and also network traffic and constrain this to a single host unless in failure.