On Tue, 17 Oct 2017, Yoann Moulin wrote: > Hello, > > I wonder if it's possible to add to ceph the ability to rebuild a new disk automatically freshly added to a slot in replacement of a failed osd > disk. > > I imagine something like adding a flag on disks (identified by-path for example or a way to have a deterministic access to the device) to be > auto-reconfigured if detected with no data after the same slot was marked as failed. Only disks identified "by-path" with an auto-rebuild flag > activated, and previously marked as failed, can run the auto-reconfiguration. > > I know it should take some time to find the best way to implement that feature to avoid zapping a disk with data but that would be great to > improve maintainability. The way that we approached this before with ceph-disk was that you would prelabel replacement disks as "blank ceph" or similar. That way if we saw a ceph labeled disk that hadn't been used yet we would know it was fair game. This is a lot more work for the admin (you have to attached each of your replacement disks to mark them and then put them in the replacement pile) but it is safer. An alternative model would be to have a reasonably reliable way to identify a fresh disk from the factory. I'm honest not sure what new disks look like these days (zero? empty NTFS partition?) but we could try to recognized "blank" and go from there. Unfortunately we can't assume blank if we see garbage because the disk might be encrypted. Anyway, assuming that part was sorted out, I think a complete solution would query the mons to see what OSD id used to live in that particular by-path location/slot and try to re-use that OSD ID. We have still built in a manual task here of marking the failed osd "destroyed" since reusing the ID means the cluster may make assumptions about PG copies on the OSD being lost. sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
