We have a need to shrink the C: drive (and go from thick to thin provisioning) of 4 Domain Controller VMs that have HA and FT enabled. I performed a test on a system with identical disk/provisioning but it was not part of a cluster nor was it HA-FT enabled. I just wanted to ask if anyone had done anything similar, and what problems the HA and FT being enabled could cause. I am going to work next on doing an apples to apples comparison on a test cluster now that my initial testing was successful, but I thought it worthwhile to ask here to see if anyone had any experience with this.
ESXi 5.5 and Windows Server 2008 R2 on the VMs
Fault Tolerance on vSphere 5.x virtual machine requires disk with Thick Eager Zeroed... so, if you decide convert your virtual machine disks from thick to thin, you will not able to use FT until you convert your disk back to thick. A good news, is that FT on vSphere 6 do not required that this are Thick Eager Zeroed anymore. Anyway, you really need to use FT on your domain controllers since you have more than two domain controllers ?
thanks for the clarification. Technically I don't need to convert them to thin provisioned disks, I just need to recover the wasted space on each VM. As far as FT and needing it, these are customer servers that we're hosting and we may be contractually obligated to provide them this configuration. This configuration was done before I came along. Maybe I'll see if I can dig up some info on why it was provisioned this way.