Wouter et al, I am thinking of adding the following commands to NBD:
NBD_CMD_SNAPSHOT: generate a snapshot of the disk in its existing form. Return to the client an export name that can be mounted. NBD_CMD_RESIZE: change the size of an existing disk (generally enlarging the disk is more useful than making it smaller). NBD_CMD_DISC2: like existing disconnect command, save that it sends a reply, so you know when it's actually completed (the current one sends no reply); this is relevant if you want to know (say) when it is safe to remount it. I'd also like to introduce a flag into NBD_CMD_DISC2 which will cause the backing store for the disk to be deleted (if honoured by the server). SNAPSHOT & RESIZE will need to be implemented through adding to the ioctl code (i.e. they will need kernel changes). For the moment I propose snapshot to work like lvm snapshots, i.e. be pretty dumb and leave quiescing the write stream, ensuring disk consistency etc. as an "interesting problem for the user". Using NBD_CMD_DISC2 would require a kernel code change too, though I'd leaving it supporting NBD_CMD_DISC when called with existing parameters. I'm happy to implement these on nbd-client & ndb-server and write a test suite for them. I have to be honest and say some of my motivation for this is my rather specialist not-yet-open-source nbd compatible server. I think SNAPSHOT, RESIZE and DISC2 are genuinely useful for mainstraim nbd, but the delete option is probably only really of use where there isn't a configuration file that would also need editing. Any opinions? -- Alex Bligh ------------------------------------------------------------------------------ Got Input? Slashdot Needs You. Take our quick survey online. Come on, we don't ask for help often. Plus, you'll get a chance to win $100 to spend on ThinkGeek. http://p.sf.net/sfu/slashdot-survey _______________________________________________ Nbd-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nbd-general
