vim-cmd vmsvc/snapshot.removeall command took about 20 mins to finish

Experts,

I am using command line tool vim-cmd to control my Vsphere clients' snapshots.

Because I can not use vim-cmd to identify one snapshot by name, need to provide Index and Level, which I dont have. But I can always use 0 0 pair for the root snapshot.

So, I am using only one snapshot and using snapshot.removeall to remove the root snapshot.

But sometimes vmsvc/snapshot.removeall command took too much time to execute, I dont know why, anyone who can direct me? Or I should choose remove but not remove all?

Thanks!

Tyler