I am new in the snapshot world. I read that "The time
taken to develop a snapshot depends on the amount of data and the load on the server.
On average, the time ranges from 30 to 40 seconds for minimal snapshot creation."
but what means minimal snapshot? How long does a snapshot take approx. for let's say 2 TB? During the whole snapshot creation time the users are not able to work on the virtual machine at that time?
Yes, during the snapshot creation time I/O is temporarily suspended (I have noticed this more when the snapshot memory is also checked).
I haven't snapshotted a 2TB VM but wonder if this is the best solution to your problem. The key thing to consider is not to leave a snapshot in place for an extended period of time especially if the data changes a lot. People have found that when deleting a snapshot it can take a long time or even time out.
I have found using snapshots very useful for short-term recovery i.e. when testing a hotfix or a change control. So the question remains as to what role the VM is performing and how long you intent to keep your snapshot?
I just snapshotted a Windows 2003 SP1 VM with a 10GB C: drive. I ran a disk throughtput tester utility, started a snapshot which "paused" the utility for less than 15 seconds. Then, I/O resumed, no issues. Crude but gives you some insight.