ddf failed disk disappears after adding spare
Hi Neil,
here is a procedure which shows you another problem. It has to do with the table produced at the end of the mdadm -E command, showing the disks and their status. Seems when a disk has failed and another added, the failed one disappears.
Hope you can find the problem and fix it.
Regards,
Albert
Here is the exact procedure which shows the problem:
Create a container with 5 disks:
mdadm -CR /dev/md127 -e ddf -l container -n 5 /dev/loop[1-5]
Physical Disks : 5
Number RefNo Size Device Type/State
0 d1c8c16e 479232K /dev/loop1 Global-Spare/Online
1 6de79cb6 479232K /dev/loop2 Global-Spare/Online
2 b5fd1d6c 479232K /dev/loop3 Global-Spare/Online
3 0be2d310 479232K /dev/loop4 Global-Spare/Online
4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 5 set of 3 disks in container:
mdadm -CR /dev/md0 -l 5 -n 3 /dev/md127
Physical Disks : 5
Number RefNo Size Device Type/State
0 d1c8c16e 479232K /dev/loop1 active/Online
1 6de79cb6 479232K /dev/loop2 active/Online
2 b5fd1d6c 479232K /dev/loop3 active/Online
3 0be2d310 479232K /dev/loop4 Global-Spare/Online
4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 1 set of 2 disks in container:
mdadm -CR /dev/md1 -l 1 -n 2 /dev/md127
Physical Disks : 5
Number RefNo Size Device Type/State
0 d1c8c16e 479232K /dev/loop1 active/Online
1 6de79cb6 479232K /dev/loop2 active/Online
2 b5fd1d6c 479232K /dev/loop3 active/Online
3 0be2d310 479232K /dev/loop4 active/Online
4 5d8ac3d0 479232K /dev/loop5 active/OnlineFail first disk in RAID 5 set:
mdadm -f /dev/md0 /dev/loop1
Physical Disks : 5
Number RefNo Size Device Type/State
0 d1c8c16e 479232K /dev/loop1 active/Offline, Failed
1 6de79cb6 479232K /dev/loop2 active/Online
2 b5fd1d6c 479232K /dev/loop3 active/Online
3 0be2d310 479232K /dev/loop4 active/Online
4 5d8ac3d0 479232K /dev/loop5 active/OnlineRemove failed disk:
mdadm -r /dev/md0 /dev/loop1
Physical Disks : 5
Number RefNo Size Device Type/State
0 d1c8c16e 479232K active/Offline,
Failed, Missing
1 6de79cb6 479232K /dev/loop2 active/Online
2 b5fd1d6c 479232K /dev/loop3 active/Online
3 0be2d310 479232K /dev/loop4 active/Online
4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd failed disk back:
mdadm -a --force /dev/md0 /dev/loop1
Physical Disks : 5
Number RefNo Size Device Type/State
0 d1c8c16e 479232K /dev/loop1 active/Offline,
Failed, Missing
1 6de79cb6 479232K /dev/loop2 active/Online
2 b5fd1d6c 479232K /dev/loop3 active/Online
3 0be2d310 479232K /dev/loop4 active/Online
4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd spare disk to container:
mdadm -a --force /dev/md0 /dev/loop6
Physical Disks : 5
Number RefNo Size Device Type/State
0 6de79cb6 479232K /dev/loop2 active/Online
1 b5fd1d6c 479232K /dev/loop3 active/Online
2 0be2d310 479232K /dev/loop4 active/Online
3 5d8ac3d0 479232K /dev/loop5 active/Online
4 1dcfe3cf 479232K /dev/loop6 active/Online, RebuildingThis is wrong! Physical disks should be 6 now!
Removed failed disk (which is missing from list now!) again, zero superblock and add again:
mdadm -r /dev/md0 /dev/loop1
mdadm --zero-superblock /dev/loop1
mdadm -a --force /dev/md0 /dev/loop1
Physical Disks : 6
Number RefNo Size Device Type/State
0 6de79cb6 479232K /dev/loop2 active/Online
1 b5fd1d6c 479232K /dev/loop3 active/Online
2 0be2d310 479232K /dev/loop4 active/Online
3 5d8ac3d0 479232K /dev/loop5 active/Online
4 1dcfe3cf 479232K /dev/loop6 active/Online
5 8147a3ef 479232K /dev/loop1 Global-Spare/OnlineAnd there they are, all 6 of them.
Hi Neil,
looking at it again I think the following happened:
When the disk was removed, the entry got the status "missing", which is correct. When I re-added the same disk (actually I used add, re-add doesn't work with containers) the "missing" status isn't cleared, as can be seen.
But it is recognised as belonging to its original slot, albeit the missing status isn't cleared, the other status (failed, offline) can stay as they are.
When I now add another disk (a spare) the slot of the missing disk is re-used, as it is marked "missing". Only by removing that disk, zeroing
the superblock and adding it again, i.e. effectively adding a new disk, the total amount of slots is increased to 6.
just my two cents,
Albert
Quoted 127 lines · Albert Pauw
Hi Neil,
here is a procedure which shows you another problem. It has to do with the table produced at the end of the mdadm -E command, showing the disks and their status. Seems when a disk has failed and another added, the failed one disappears.
Hope you can find the problem and fix it.
Regards,
Albert
Here is the exact procedure which shows the problem:
Create a container with 5 disks:
mdadm -CR
/dev/md127-e ddf -l container -n 5 /dev/loop[1-5]Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 Global-Spare/Online 1 6de79cb6 479232K /dev/loop2 Global-Spare/Online 2 b5fd1d6c 479232K /dev/loop3 Global-Spare/Online 3 0be2d310 479232K /dev/loop4 Global-Spare/Online 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 5 set of 3 disks in container:
mdadm -CR
/dev/md0-l 5 -n 3/dev/md127Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Online 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 Global-Spare/Online 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 1 set of 2 disks in container:
mdadm -CR
/dev/md1-l 1 -n 2/dev/md127Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Online 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineFail first disk in RAID 5 set:
mdadm -f
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Offline, Failed 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineRemove failed disk:
mdadm -r
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K active/Offline, Failed, Missing 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd failed disk back:
mdadm -a --force
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Offline, Failed, Missing 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd spare disk to container:
mdadm -a --force
/dev/md0/dev/loop6Physical Disks : 5
Number RefNo Size Device Type/State 0 6de79cb6 479232K /dev/loop2 active/Online 1 b5fd1d6c 479232K /dev/loop3 active/Online 2 0be2d310 479232K /dev/loop4 active/Online 3 5d8ac3d0 479232K /dev/loop5 active/Online 4 1dcfe3cf 479232K /dev/loop6 active/Online, RebuildingThis is wrong! Physical disks should be 6 now!
Removed failed disk (which is missing from list now!) again, zero superblock and add again:
mdadm -r
/dev/md0/dev/loop1
mdadm --zero-superblock/dev/loop1
mdadm -a --force/dev/md0/dev/loop1Physical Disks : 6
Number RefNo Size Device Type/State 0 6de79cb6 479232K /dev/loop2 active/Online 1 b5fd1d6c 479232K /dev/loop3 active/Online 2 0be2d310 479232K /dev/loop4 active/Online 3 5d8ac3d0 479232K /dev/loop5 active/Online 4 1dcfe3cf 479232K /dev/loop6 active/Online 5 8147a3ef 479232K /dev/loop1 Global-Spare/OnlineAnd there they are, all 6 of them.
Sorry again,
just noticed that the removing of the slot of the missing drive is triggered by a rebuild. In fact, even a failed (but not missing) drive is removed as well.
I noticed this by the following:
- started with 6 disks
- created md0 with 5 disks
- failed one disk in md0
- the mdadm -E table is shown very shortly with 6 disks, one failed, but when the rebuild kicks in, the failed disk entry is removed, 5 entries remain.
Albert
Quoted 152 lines · Albert Pauw
Hi Neil,
looking at it again I think the following happened:
When the disk was removed, the entry got the status "missing", which is correct. When I re-added the same disk (actually I used add, re-add doesn't work with containers) the "missing" status isn't cleared, as can be seen.
But it is recognised as belonging to its original slot, albeit the missing status isn't cleared, the other status (failed, offline) can stay as they are.When I now add another disk (a spare) the slot of the missing disk is re-used, as it is marked "missing". Only by removing that disk, zeroing
the superblock and adding it again, i.e. effectively adding a new disk, the total amount of slots is increased to 6.just my two cents,
Albert
Quoted 127 lines · Albert Pauw
Hi Neil,
here is a procedure which shows you another problem. It has to do with the table produced at the end of the mdadm -E command, showing the disks and their status. Seems when a disk has failed and another added, the failed one disappears.
Hope you can find the problem and fix it.
Regards,
Albert
Here is the exact procedure which shows the problem:
Create a container with 5 disks:
mdadm -CR
/dev/md127-e ddf -l container -n 5 /dev/loop[1-5]Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 Global-Spare/Online 1 6de79cb6 479232K /dev/loop2 Global-Spare/Online 2 b5fd1d6c 479232K /dev/loop3 Global-Spare/Online 3 0be2d310 479232K /dev/loop4 Global-Spare/Online 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 5 set of 3 disks in container:
mdadm -CR
/dev/md0-l 5 -n 3/dev/md127Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Online 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 Global-Spare/Online 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 1 set of 2 disks in container:
mdadm -CR
/dev/md1-l 1 -n 2/dev/md127Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Online 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineFail first disk in RAID 5 set:
mdadm -f
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Offline, Failed 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineRemove failed disk:
mdadm -r
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K active/Offline, Failed, Missing 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd failed disk back:
mdadm -a --force
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Offline, Failed, Missing 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd spare disk to container:
mdadm -a --force
/dev/md0/dev/loop6Physical Disks : 5
Number RefNo Size Device Type/State 0 6de79cb6 479232K /dev/loop2 active/Online 1 b5fd1d6c 479232K /dev/loop3 active/Online 2 0be2d310 479232K /dev/loop4 active/Online 3 5d8ac3d0 479232K /dev/loop5 active/Online 4 1dcfe3cf 479232K /dev/loop6 active/Online, RebuildingThis is wrong! Physical disks should be 6 now!
Removed failed disk (which is missing from list now!) again, zero superblock and add again:
mdadm -r
/dev/md0/dev/loop1
mdadm --zero-superblock/dev/loop1
mdadm -a --force/dev/md0/dev/loop1Physical Disks : 6
Number RefNo Size Device Type/State 0 6de79cb6 479232K /dev/loop2 active/Online 1 b5fd1d6c 479232K /dev/loop3 active/Online 2 0be2d310 479232K /dev/loop4 active/Online 3 5d8ac3d0 479232K /dev/loop5 active/Online 4 1dcfe3cf 479232K /dev/loop6 active/Online 5 8147a3ef 479232K /dev/loop1 Global-Spare/OnlineAnd there they are, all 6 of them.
Quoted 100 lines · On Wed, 01 Aug 2012 10:29:51 +0200 Albert Pauw <[email protected]> wrote:
Hi Neil,
here is a procedure which shows you another problem. It has to do with the table produced at the end of the mdadm -E command, showing the disks and their status. Seems when a disk has failed and another added, the failed one disappears.
Hope you can find the problem and fix it.
Regards,
Albert
Here is the exact procedure which shows the problem:
Create a container with 5 disks:
mdadm -CR
/dev/md127-e ddf -l container -n 5 /dev/loop[1-5]Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 Global-Spare/Online 1 6de79cb6 479232K /dev/loop2 Global-Spare/Online 2 b5fd1d6c 479232K /dev/loop3 Global-Spare/Online 3 0be2d310 479232K /dev/loop4 Global-Spare/Online 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 5 set of 3 disks in container:
mdadm -CR
/dev/md0-l 5 -n 3/dev/md127Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Online 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 Global-Spare/Online 4 5d8ac3d0 479232K /dev/loop5 Global-Spare/OnlineCreate a RAID 1 set of 2 disks in container:
mdadm -CR
/dev/md1-l 1 -n 2/dev/md127Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Online 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineFail first disk in RAID 5 set:
mdadm -f
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State 0 d1c8c16e 479232K /dev/loop1 active/Offline, Failed 1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineRemove failed disk:
mdadm -r
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State
0d1c8c16e479232K active/Offline,
Failed, Missing1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd failed disk back:
mdadm -a --force
/dev/md0/dev/loop1Physical Disks : 5
Number RefNo Size Device Type/State
0d1c8c16e479232K/dev/loop1active/Offline,
Failed, Missing1 6de79cb6 479232K /dev/loop2 active/Online 2 b5fd1d6c 479232K /dev/loop3 active/Online 3 0be2d310 479232K /dev/loop4 active/Online 4 5d8ac3d0 479232K /dev/loop5 active/OnlineAdd spare disk to container:
mdadm -a --force
/dev/md0/dev/loop6Physical Disks : 5
Quoted 8 lines
Number RefNo Size Device Type/State 0 6de79cb6 479232K /dev/loop2 active/Online 1 b5fd1d6c 479232K /dev/loop3 active/Online 2 0be2d310 479232K /dev/loop4 active/Online 3 5d8ac3d0 479232K /dev/loop5 active/Online 4 1dcfe3cf 479232K /dev/loop6 active/Online, RebuildingThis is wrong! Physical disks should be 6 now!
Whenever we add a device to the ddf we currently remove any record of any failed and missing device. We have to forget about devices that have disappeared at some stage, and this seems like a good place.
The problem here is that a device that is in the array is marked as 'missing'. This due to the bug I mentioned in the previous email. Currently worked around by --zeroing the device before adding it.
Quoted 18 lines
Removed failed disk (which is missing from list now!) again, zero superblock and add again:
mdadm -r
/dev/md0/dev/loop1
mdadm --zero-superblock/dev/loop1
mdadm -a --force/dev/md0/dev/loop1Physical Disks : 6
Number RefNo Size Device Type/State 0 6de79cb6 479232K /dev/loop2 active/Online 1 b5fd1d6c 479232K /dev/loop3 active/Online 2 0be2d310 479232K /dev/loop4 active/Online 3 5d8ac3d0 479232K /dev/loop5 active/Online 4 1dcfe3cf 479232K /dev/loop6 active/Online 5 8147a3ef 479232K /dev/loop1 Global-Spare/Online
Quoted 2 lines
And there they are, all 6 of them.
NeilBrown