Greetings!
We have our vSphere 5.0U2 infrastructure set up so our DATASTORES now are either 1 terabyte or 2 terabytes. I'm setting up a new VM server (with smaller Windows system C: drives) will reside and share space on a 1 terabyte area, and I need a large file storage area for that server so I added a independent/persistent hard disk to reside on the 2 terabyte datastore. We use thick lazy zero provisioning all around and VMFS5 file systems.
Of course, one does not want to totally fill up a datastore with VMs that one may enable snapshots on, because snapshots for those system volumes can take place and be a real lifesaver if an installation/update corrupted/broke Windows. So we typically leave 20% free on those 1 terabyte server-residing datastores for VM snapshots (800GB in use, 200GB free for snapshots), so no vSphere alarms are tripped for low storage space and we avoid errors that prevent the VMs from starting or taking snapshots.
Here's where my question comes in.
Since I have this new VM where its additional "hard disk" space reside as independent/persistent disks on the 2 terabyte datastores, can we safely use the full extent of that datastore without any repercussions/errors (other than the vSphere alarm about too little free space left on the datastore)? Meaning, can we fill that 2 terabyte datastore up, rather than leave 20% of it free for snapshot use even though we might turn on snapshots for the VM?
Those independent/persistent disks are NOT being subject to snapshots & using further space on its datastore, regardless if we later turn on snapshots for its VM (the system volume part), right?
I'm being very careful so thanks so much for your answers of clarification before I roll out this server, the first of its kind.