Snapshots created with VMware tools are called managed snapshots. Snapshots created by external means, such the FlashArray GUI, CLI, and REST interfaces and protection group policies, are referred to as unmanaged. The only difference between the two is that VMware tools can be used with managed snapshots, whereas unmanaged ones must be managed with external tools.
Unmanaged snapshots (and volumes) can be used in the VMware environment. For example, FlashArray tools can copy an unmanaged source snapshot or volume to a target data vVol, overwriting the latter’s contents, but with some restrictions:
Volume size
A source snapshot or volume must be of the same size as the target data vVol. FlashArrays can copy snapshots and volumes of different sizes (the target resizes to match the source), but VMware cannot accommodate external vVol size changes. To overwrite a data vVol with a snapshot or volume of a different size, use VMware tools to resize the target vVol prior to copying.
Offline copying
Overwriting a data vVol while it is in use typically causes the application to fail or produce incorrect results. A vVol should be offline to its VM, or the VM should be powered off before overwriting.
Config vVols
Config vVols should only be overwritten with their own snapshots.
Memory vVols
Memory vVols should never be overwritten. There is no reason to overwrite them, and doing so renders them unusable.