> Surely, FUSE is another possible option, I think. I heard that lunr > team was thinking about the approach too.
I'm concerned about the performance/stability of FUSE, but I'm not sure if using iSCSI is a significantly better option when the access is likely to be local. If I had to choose something in-between, I'd evaluate if NBD was any better of a solution. I expect there will be great demand for an implementation of a Swift as a block device client. Care should be made in deciding what will be the best-supported method/implementation. That said, you have an implementation, and that goes a long way versus the alternatives which don't currently exist. > As I wrote in the previous mail, the tricky part of the dm-snapshot > approach is getting the delta of snaphosts (I assume that we want to > store only deltas on Swift). dm-snapshot doesn't provide the > user-space API to get the deltas. So Lunr needs to access to > dm-snapshot volume directly. It's sorta backdoor approach (getting the > information that Linux kernel doesn't provide to user space). As a > Linux kernel developer, I would like to shout at people who do such :) With dm-snapshot, the solution is to look at the device mapper table (via the device mapper API) and access the backend volume. I don't see why this is a bad solution. In fact, considering that the device mapper table could be arbitrarily complex and some backend volumes might be entirely virtual, i.e. dm-zero, this seems fairly reasonable to me. I really don't see at all how Swift-as-block-device relates at all to (storage) snapshots, other than the fact that this makes it possible to use Swift with dm-snapshot. Regards, Eric Windisch e...@cloudscaling.com _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
