Should the virtual hard disks for a production vCenter Server which has high performance needs in an enviornment of 100 physical servers and 3000 Virtual Machines be provisioned as Lazy or Eager Zeroed? One virtual hard disk is for the OS and the other is where I install vCenter and all it's components. If eager zeroed gives a recommended performance gain due to not having to zero during a write, should both disks be eager zeroed in this case?
Personally, I'd go for the eager zero. vCenter is pretty important, so you should protect its storage by allocating it up front. The last thing you want is to run out of space on your LUN and watch vCenter grind to a halt.
vCenter itself doesn't need that much performance - you should focus more on the performance of the vCenter DB machine (which, for an environment your size, needs to be a second host/VM).