[pve-devel] [PATCH 5/5] DRBD: Implement snapshots.

[Dietmar Maurer]

> > Maybe you already found a better way to implement rollback within
> > drbdmanage?
> Not atomically, no.
> 
> We've got an even more interesting problem - we should do atomic changes 
> across the whole cluster...

Yes, I see ;-)

> We'll probably have to do the indirection trick - storing the ProxMox names 
> in some hash table to index the resource names, and doing an atomic update 
> in that one; then all new "attach" commands would take the new resource.

I think that will work.

> Don't know how you would get the LVM sequence atomically... well, you could 
> "lvcreate" *first*, and then do a name-swap via sed/awk/perl and
> vgcfgrestore...
> 
> Ouch.
> 
> 
> I guess the most clean way would be to change "lvrename" to allow multiple 
> renames in an atomic way - but that's a bit of work.

That is what I thought too. For us it would be good enough if lvrename can
overwrite
existing devices when using the --force flag ...