What I've been playing with is having a manifest that contains hashes of (4mb) chunks for the volume's backups. When a user initiates a new backup, dm-snapshot does its thing and gives me a block device. I read and hash chunks from that block device and compare them to the manifest, uploading any that differ to Swift, then update the manifest with the new backup.
The restore uses fuse with some basic bitmap logic to lazy load chunks from Swift on demand, plus a background thread that fills them in autonomously. I've been pretty happy with fuse's performance and stability (python-fuse that is; fusepy is really slow). The NBD solution isn't really any different logic-wise from the fuse version, but requires a lot more wrangling of server and client processes. And actually we weren't too impressed with the performance of a basic NBD server in some (non-scientific) tests. All of this is sort of at the proof of concept stage at the moment. -- Michael Barton _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : [email protected] Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
