We are currently not using resource pools within our environment. What we are looking to do is implement resource pools with memory reservations based upon our VM sizes. For example, we'll create a 4GB resource pool for VMs with 4GB of memory, an 8GB resource pool for VMs with 8GB of memory, etc. We would then set the memory reservation to half (of the VM) for each pool. So the 4GB VM will have a 2GB reservation. Our aim in doing this is reduce the size of our swap files. We have a few VMs spread out in our environment that are independently configured. For example, a 12GB VM with a 6GB reservation has a 6GB swap file. On a global level, this could save us a lot of datastore space.
A few questions in doing this though. What will happen for VMs that already have reservations enabled? Does the resource pool override individual VM settings?
And does anyone see this as having any adverse effects for an HA event? We have had issues in the past in a different environment with reservations (large 38GB+ reservations), and when we lost a host VMs were unable to power on due to there being no more resources available.