[pve-devel] create snapshots

[Alexandre DERUMIER]

1.) snapshot_start 

* this is the first part of do_savevm() till vm_stop 

2.) dump_vm_state (or maybe we do this is step 1) 

* write state to some fd 

>> qmp command timeout during the vm_state dump. Maybe this is same thing that at the end of a livemigration?

I'm looking for a way for nexenta.
One way : extend the volume size, and write the vm_state dump at the end . (I don't know how to tell the beginning sector)
Second way : create a nexenta volume to write to dump.

3.) snapshot_drive 

* simply call bdrv_snapshot_create(bs1, sn) for a single drive 

4.) snapshot_end 

>>* resume the VM (maybe this is a normal resume, so we can use the existing 'cont' 
>>command) 

I confirm that "cont" command works



Also, I think we need to implement some new status , as monitor command are async, 
we need to check when the command is finished.