Hi,
I ran into a situation where my incremental backups using send|receive
are failing after a full file system failure followed by restore from an
external backup. The reason for the failures seem to be that the
Received UUID of snapshots and backups are not properly updated. In
short, everything (snapshots and backups) from the time of restore
onward has the same Received UUID. Here is an example:
[root@ldiamond-desktop test_btrfs]# btrfs sub create test1
Create subvolume './test1'
[root@ldiamond-desktop test_btrfs]# echo '1' > test1/test
[root@ldiamond-desktop test_btrfs]# btrfs sub snap -r test1/ test1_snap
Create a readonly snapshot of 'test1/' in './test1_snap'
[root@ldiamond-desktop test_btrfs]# btrfs send test1_snap/ | btrfs receive
/media/backup/test_btrfs/
At subvol test1_snap/
At subvol test1_snap
[root@ldiamond-desktop test_btrfs]# echo '2' >> test1/test
[root@ldiamond-desktop test_btrfs]# btrfs sub snap -r test1 test1_snap2
Create a readonly snapshot of 'test1' in './test1_snap2'
[root@ldiamond-desktop test_btrfs]# btrfs send test1_snap2 -p test1_snap |
btrfs receive /media/backup/test_btrfs/
At subvol test1_snap2
At snapshot test1_snap2
[root@ldiamond-desktop test_btrfs]# btrfs sub show test1
/media/btr0/test_btrfs/test1
Name: test1
UUID: 6eb0318e-f036-7840-a39f-f9f56b3769f4
Parent UUID: -
Received UUID: -
Creation time: 2017-05-05 12:29:16 -0400
Subvolume ID: 698
Generation: 11566
Gen at creation: 11558
Parent ID: 5
Top level ID: 5
Flags: -
Snapshot(s):
test_btrfs/test1_snap
test_btrfs/test1_snap2
[root@ldiamond-desktop test_btrfs]# btrfs sub show test1_snap
/media/btr0/test_btrfs/test1_snap
Name: test1_snap
UUID: 8afd7fec-5141-7b46-af05-77c78b051977
Parent UUID: 6eb0318e-f036-7840-a39f-f9f56b3769f4
Received UUID: -
Creation time: 2017-05-05 12:30:17 -0400
Subvolume ID: 700
Generation: 11561
Gen at creation: 11561
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
[root@ldiamond-desktop test_btrfs]# btrfs sub show test1_snap2
/media/btr0/test_btrfs/test1_snap2
Name: test1_snap2
UUID: fc8a9859-962d-954b-92df-32ef31b88bc9
Parent UUID: 6eb0318e-f036-7840-a39f-f9f56b3769f4
Received UUID: -
Creation time: 2017-05-05 12:32:46 -0400
Subvolume ID: 702
Generation: 11566
Gen at creation: 11566
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
[root@ldiamond-desktop test_btrfs]# btrfs sub d test1 test1_snap*
Delete subvolume (no-commit): '/media/btr0/test_btrfs/test1'
Delete subvolume (no-commit): '/media/btr0/test_btrfs/test1_snap'
Delete subvolume (no-commit): '/media/btr0/test_btrfs/test1_snap2'
[root@ldiamond-desktop test_btrfs]# btrfs send
/media/backup/test_btrfs/test1_snap2/ | btrfs receive ./
At subvol /media/backup/test_btrfs/test1_snap2/
At subvol test1_snap2
[root@ldiamond-desktop test_btrfs]# btrfs property set -ts test1_snap2/ ro
false
[root@ldiamond-desktop test_btrfs]# echo '3' >> test1_snap2/test
[root@ldiamond-desktop test_btrfs]# cat test1_snap2/test
1
2
3
[root@ldiamond-desktop test_btrfs]# btrfs sub snap -r test1_snap2/
test1_snap3
Create a readonly snapshot of 'test1_snap2/' in './test1_snap3'
[root@ldiamond-desktop test_btrfs]# btrfs send test1_snap3/ | btrfs receive
/media/backup/test_btrfs/
At subvol test1_snap3/
At subvol test1_snap3
[root@ldiamond-desktop test_btrfs]# echo '4' >> test1_snap2/test
[root@ldiamond-desktop test_btrfs]# btrfs sub snap -r test1_snap2/
test1_snap4
Create a readonly snapshot of 'test1_snap2/' in './test1_snap4'
[root@ldiamond-desktop test_btrfs]# btrfs send test1_snap4/ -p test1_snap3/
| btrfs receive /media/backup/test_btrfs/
At subvol test1_snap4/
At snapshot test1_snap4
[root@ldiamond-desktop test_btrfs]# btrfs sub show test1_snap2
/media/btr0/test_btrfs/test1_snap2
Name: test1_snap2
UUID: 5f505e2f-2e0a-8840-8132-08ba3bdb4484
Parent UUID: -
Received UUID: fc8a9859-962d-954b-92df-32ef31b88bc9
Creation time: 2017-05-05 12:34:25 -0400
Subvolume ID: 703
Generation: 11579
Gen at creation: 11569
Parent ID: 5
Top level ID: 5
Flags: -
Snapshot(s):
test_btrfs/test1_snap3
test_btrfs/test1_snap4
[root@ldiamond-desktop test_btrfs]# btrfs sub show test1_snap3
/media/btr0/test_btrfs/test1_snap3
Name: test1_snap3
UUID: 6321f351-2a36-b94b-b2a3-85250eecc4fb
Parent UUID: 5f505e2f-2e0a-8840-8132-08ba3bdb4484
Received UUID: fc8a9859-962d-954b-92df-32ef31b88bc9
Creation time: 2017-05-05 12:36:00 -0400
Subvolume ID: 704
Generation: 11575
Gen at creation: 11575
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
[root@ldiamond-desktop test_btrfs]# btrfs sub show test1_snap4
/media/btr0/test_btrfs/test1_snap4
Name: test1_snap4
UUID: 4863c19e-48ba-ce49-892a-4f98f101ffb8
Parent UUID: 5f505e2f-2e0a-8840-8132-08ba3bdb4484
Received UUID: fc8a9859-962d-954b-92df-32ef31b88bc9
Creation time: 2017-05-05 12:37:38 -0400
Subvolume ID: 706
Generation: 11579
Gen at creation: 11579
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
[root@ldiamond-desktop test_btrfs]# btrfs sub show
/media/backup/test_btrfs/test1_snap
test1_snap/ test1_snap2/ test1_snap3/ test1_snap4/
[root@ldiamond-desktop test_btrfs]# btrfs sub show
/media/backup/test_btrfs/test1_snap
/media/backup/test_btrfs/test1_snap
Name: test1_snap
UUID: dd86dd56-0dfe-4f48-b040-6b12fcc07965
Parent UUID: -
Received UUID: 8afd7fec-5141-7b46-af05-77c78b051977
Creation time: 2017-05-05 12:31:03 -0400
Subvolume ID: 1163
Generation: 2813
Gen at creation: 2810
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
test_btrfs/test1_snap2
[root@ldiamond-desktop test_btrfs]# btrfs sub show
/media/backup/test_btrfs/test1_snap2
/media/backup/test_btrfs/test1_snap2
Name: test1_snap2
UUID: 957baf65-eb56-7546-8d22-dca29733fdd3
Parent UUID: dd86dd56-0dfe-4f48-b040-6b12fcc07965
Received UUID: fc8a9859-962d-954b-92df-32ef31b88bc9
Creation time: 2017-05-05 12:32:55 -0400
Subvolume ID: 1164
Generation: 2820
Gen at creation: 2813
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
test_btrfs/test1_snap4
[root@ldiamond-desktop test_btrfs]# btrfs sub show
/media/backup/test_btrfs/test1_snap3
/media/backup/test_btrfs/test1_snap3
Name: test1_snap3
UUID: 6e2369f8-dd57-fd4c-9ef9-8467cf1eb00f
Parent UUID: -
Received UUID: fc8a9859-962d-954b-92df-32ef31b88bc9
Creation time: 2017-05-05 12:36:38 -0400
Subvolume ID: 1165
Generation: 2818
Gen at creation: 2817
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
[root@ldiamond-desktop test_btrfs]# btrfs sub show
/media/backup/test_btrfs/test1_snap4
/media/backup/test_btrfs/test1_snap4
Name: test1_snap4
UUID: d255acb5-cc6c-0141-a697-071ebdbb8771
Parent UUID: 957baf65-eb56-7546-8d22-dca29733fdd3
Received UUID: fc8a9859-962d-954b-92df-32ef31b88bc9
Creation time: 2017-05-05 12:37:56 -0400
Subvolume ID: 1166
Generation: 2821
Gen at creation: 2820
Parent ID: 5
Top level ID: 5
Flags: readonly
Snapshot(s):
These are my kernel/btrfs versions
$ uname -a
Linux ldiamond-desktop 4.10.11-1-ARCH #1 SMP PREEMPT Tue Apr 18 08:39:42 CEST
2017 x86_64 GNU/Linux
ldiamond@ldiamond-desktop ~/tmp
$ btrfs --version
btrfs-progs v4.10.2
ldiamond@ldiamond-desktop ~/tmp
$
Are those Received UUIDs the expected values for the provided test-case? Aren't
the Received UUID always supposed to reflect the sent subvolume UUID value?
Thanks,
Lewis Diamond
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