VMware - Snapshot explained

In VMware the snapshot file grows by 16MB block size. Now there is no formula out there that you can use to predetermine the size of the snapshot beforehand. 

But VMware's best practice is to keep the snapshot no more then 24-72 hours & 1-2 snapshots per VM. Snapshot files will grow to the maximum size of the original disk, to avoid any problems and to mitigate future issues either delete the snapshot or consolidate it when you are happy that your VM is running as it should be.

Now I’ve taken some screenshots of a virtual machine with the memory and quiesce options to show the size of the snapshots.

1: What the snapshot options look like.

2: This shows the state of the files before any snapshots. See that the vswp file is 4GB in size, that is the memory that was allocated to the server during creation.

3: The 1st snapshot I took was with the memory option which by the way is the default. As you can see the size of the delta.vmdk file is 16MB and that the vmsn file is 4GB in size, which is the size of the memory in the virtual server.

4: The 2nd snapshot was taken with only the "quiesce" option ticked and as you can see the delta.vmdk file is still 16MB but the vmsn file is only 31K. The reason is because there were no real disk I/O happening on the server at the time of the snapshot.

5: The 3rd snapshot was taken with both the "memory& quiesce" options ticked. The delta.vmdk is still 16MB, but the vmsn file is a combination of the memory and disk state.