Hello
We are running ESX4.1 and vCenter 4.0 on some old IBM servers and are looking to upgrade to the latest version of ESX and vCenter. We would also like to do a refresh of our VMs as we have a mish-mash of some VMs which run multiple apps, and other VMs which run a single app alone (eg domain controllers, exchange)
I think there are some benefits to running multiple apps on the same VM- less memory used by VMs, less scheduling overhead.
There are also benefits to giving each app it's own VM- isolation, and the ability to configure the operating system for the app.
I'm just wondering if it's better to combine all these apps into one server with a lot of RAM and let the guest OS handle the allocation of system resources to each app, or to give each app a seperate VM with minimal RAM and let ESX schedule the resources.
Same question applies for the database tier, is it better to have one SQL server and point all your apps to that or have seperate SQL servers for each app?
Of course some apps are meant to be kept on their own VM, such as the domain controller and our exchange setup.
Regards, Sam