[pve-devel] Disk cloning feature for shared lvm storage

[Stefan Priebe - Profihost AG]

Am 14.10.2011 11:14, schrieb Dietmar Maurer:
>> OpenVZ:
>> - moving from the same to the same node doesn't make sense as it is only a
>> directory and OpenVZ doesn't know more than a root fs
>
> maybe in future
>
>> - copying can make sense so copying should work
>>
>> KVM:
>> - moving from the same to the same node should work but we have to handle
>> two situations.
>>      - 1. shared storage =>  just renaming the LVM storage to be now a member of
>> VMID XYZ ?
>>      - 2. not a shared storage =>  moving does not work - except we dump image to
>> local disk then copy via rsync and then restore the image to LVM disk.
>
> would be greate if we have that too - although I want to avoid extra copies to local disk somehow.

OK so copying and moving should be handled by storage_migrate? Do we 
need to rename it in that case? Should i add a flag like $delete_src? So 
storage_migrate can do copy and move actions. Oder should i add an 
action parameter which can be copy or move?

Should we block / stop the action if the src volume is in use? How can 
we check that?

Then our decisions how to handle the action are based on:
action (copy/move)
storage_id (src != dst or src = dst)
type (dir/nfs/lvm)
shared (1/0)

I think we should then write down what should happen on each cobination. 
I'm not so familar with lvm so i def. need help with that. As we have a 
lot of different combinations any idea on how to write them down so that 
they're still readable?



Stefan