[sheepdog] [PATCH 1/2] collie: add command 'collie vdi rollback'

[MORITA Kazutaka]

At Fri, 31 Aug 2012 17:09:22 +0800,
levin li wrote:
> 
> 
> I still don't understand what's the use of your rollback of a snapshot, it seems

A rollback operation is supported by many systems.  See their use
cases.

> it just move the current VDI to the specified snapshot VDI and created a new one,
> but what's the use of the current VDI ?

As I said before, we should remove the previous current VDI.  My patch
was just a draft.

> 
> In my scenario, we clone a VDI from a snapshot, and the cloned VDI is modified after
> VM running, but we want to reset the VDI back to the initial state, I think this is
> useful for me and many users,
> but I don't quite understand the use of your rollback
> scenario, maybe I can go back to rename the command as *'reset'* to just reset a cloned
> VDI, what do you think about it?

We can do the same thing by deleting and recreating the vdi.  The
benefits of the 'vdi reset' command is only performance?  If so, to be
honest, I don't like to merge it.  I don't understand why we need a
performance for reseting cloned vdis.

Thanks,

Kazutaka