δΊ 2013-1-24 13:51, Dietmar Maurer ει:
* Like Case 2, the benefit isn't clear to me. In a scenario where you
use both QEMU and LVM snapshots there is now an extra management
overhead of cleaning up 2 snapshots instead of just 1 when the user
wants to delete a snapshot. I think this will be a headache.
My understanding is internal snapshots is obvious fast in both deleting and
reading, and I have similar questions, Dietmar, could u tip more how you use
this case while 2 snapshot layer exist?
To be honest, I don't really understand what you talk about here. There are
simply
different storage types and file formats. There are several storage types with
support for internal snapshots:
* traditional qcow2 files on normal file system
* newer file systems (zfs, btrfs)
* lvm (new dm-thin pools)
* RDB (ceph)
* sheepdog
* iSCSI and nexenta API
*...
And you simply want to allow an external library to create/remove the snapshot
for you.
I remember you have a patch enable take qcow2 internal snapshot for
every block device, and then will you use LVM to take another LVM
snapshot for it? If not how did you treat this qcow2 internal snapshot
later?
--
Best Regards
Wenchao Xia