27.02.2018 01:54, Emil.s пишет: > Hello, > > I'm trying to restore a subvolume from a backup, but I'm failing when > I try to setup the replication chain again. > > Previously I had disk A and B, where I was sending snapshots from A to > B using "send -c /disk_a/1 /disk_a/2 | receive /disk_b" and so on. > Now disk A failed, so I got a new disk: C. > > First I sent the last backup from B to C by running "send disk_b/2 | > receive /disk_c/". > > Then my plan was to use disk B as the new main disk, so on disk B, I > created a new snapshot by running "snapshot -r disk_b/2 > disk_b/my_volume". > Now I want to send "disk_b/my_volume" to disk C, so that I can set > disk_b/2 to RW and start using it again, but the last send fails with > "ERROR: cannot find parent subvolume". > > Disk B: > root@tillberga: /backup #> btrfs subvol sh snapshots/user_data_2018-02-17/ > snapshots/user_data_2018-02-17 > Name: user_data_2018-02-17 > UUID: 93433261-d954-9f4b-8319-d450ae079a9a > Parent UUID: 51180286-c202-c94c-b8f9-2ecc8d2b5b7c > Received UUID: 014fc004-ae04-0148-9525-1bf556fd4d10 > Flags: readonly > Snapshot(s): > user_data_test > > Disk C: > root@hedemora: /btrfs #> btrfs subvol sh user_data_2018-02-17/ > user_data_2018-02-17 > Name: user_data_2018-02-17 > UUID: 35361429-a42c-594b-b390-51ffb9725324 > Parent UUID: - > Received UUID: 93433261-d954-9f4b-8319-d450ae079a9a > Flags: readonly > Snapshot(s): > > Disk B has UUID 93433261-d954-9f4b-8319-d450ae079a9a, and disk C has > "Received UUID: 93433261-d954-9f4b-8319-d450ae079a9a". I think that's > alright? > > The new snapshot on disk B looks as following: > root@tillberga: /backup #> btrfs subvol sh user_data_test > user_data_test > Name: user_data_test > UUID: bf88000c-e3a6-434b-8f69-f5ce2174227e > Parent UUID: 93433261-d954-9f4b-8319-d450ae079a9a > Received UUID: 014fc004-ae04-0148-9525-1bf556fd4d10 > Flags: readonly > Snapshot(s): > > But when I'm trying to send it, I'm getting the following: > root@tillberga: /backup #> btrfs send -v -c > snapshots/user_data_2018-02-17 user_data_test | ssh user@hedemora > "sudo btrfs receive -v /btrfs/" > At subvol user_data_test > BTRFS_IOC_SEND returned 0 > joining genl thread > receiving snapshot user_data_test > uuid=014fc004-ae04-0148-9525-1bf556fd4d10, ctransid=52373 > parent_uuid=014fc004-ae04-0148-9525-1bf556fd4d10, > parent_ctransid=52373 > At snapshot user_data_test > ERROR: cannot find parent subvolume > > Note that the receiver says > "parent_uuid=014fc004-ae04-0148-9525-1bf556fd4d10". Not really sure > where that comes from, but disk B has the same, so maybe that's the > UUID of the original snapshot on disk A? >
If "Received UUID" is set on a subvolume, "btrfs send" will forward it and set on destination unchanged, instead of computing "correct" Received UUID. This has been discussed several times. > Is it possible to continue to send incremental snapshots between these > two file systems, or must I do a full sync? You would need to create writable clone on B first and start with this clone; new writable clone won't have (misleading) Received UUID and you start clean. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
