Hi folks,
I don't know if this problem is known (and if it's considered as
normal?). It happens on mdadm 4.1-1 and 3.4-4. I noticed it during my
tests this weekend. It's not critical as the array can be assembled
again manually.
If I create a RAID0 with 2 drives (and it's running fine):
mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdc1 /dev/sdd1
# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun May 5 18:53:39 2019
Raid Level : raid0
Array Size : 4091904 (3.90 GiB 4.19 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Sun May 5 18:53:39 2019
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Chunk Size : 512K
Consistency Policy : none
Name : Camera-PC:0 (local to host Camera-PC)
UUID : e3b954a6:ab381819:0aab441c:e1557ee4
Events : 0
Number Major Minor RaidDevice State
0 8 33 0 active sync /dev/sdc1
1 8 49 1 active sync /dev/sdd1
Then I play --add with some 3rd disk
mdadm --manage /dev/md0 --add /dev/sde1
mdadm: add new device failed for /dev/sde1 as 2: Invalid argument.
Nothing seems to have happened, mdadm --detail /dev/md0 shows no change.
But the /dev/sde1 disk is now shown as Linux RAID member (version 1.2)
and using the same UUID like the 2 others: it has been like prepared as
a spare member of the array.
root@Camera-PC:/home/user# mdadm --examine /dev/sdc1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : e3b954a6:ab381819:0aab441c:e1557ee4
Name : Camera-PC:0 (local to host Camera-PC)
Creation Time : Sun May 5 18:53:39 2019
Raid Level : raid0
Raid Devices : 2
Avail Dev Size : 4091904 (1998.00 MiB 2095.05 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4016 sectors, after=0 sectors
State : clean
Device UUID : b3d9733c:009fea7e:f5b4ffb3:0bfa381a
Update Time : Sun May 5 18:53:39 2019
Bad Block Log : 512 entries available at offset 8 sectors
Checksum : 62a315de - correct
Events : 0
Chunk Size : 512K
Device Role : Active device 0
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
root@Camera-PC:/home/user# mdadm --examine /dev/sdd1
/dev/sdd1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : e3b954a6:ab381819:0aab441c:e1557ee4
Name : Camera-PC:0 (local to host Camera-PC)
Creation Time : Sun May 5 18:53:39 2019
Raid Level : raid0
Raid Devices : 2
Avail Dev Size : 4091904 (1998.00 MiB 2095.05 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4016 sectors, after=0 sectors
State : clean
Device UUID : fbc9fbbe:db663cf8:9221f6f4:5701f13c
Update Time : Sun May 5 18:53:39 2019
Bad Block Log : 512 entries available at offset 8 sectors
Checksum : c22b41ec - correct
Events : 0
Chunk Size : 512K
Device Role : Active device 1
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
root@Camera-PC:/home/user# mdadm --examine /dev/sde1
/dev/sde1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : e3b954a6:ab381819:0aab441c:e1557ee4
Name : Camera-PC:0 (local to host Camera-PC)
Creation Time : Sun May 5 18:53:39 2019
Raid Level : raid0
Raid Devices : 2
Avail Dev Size : 4091904 (1998.00 MiB 2095.05 MB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
Unused Space : before=4016 sectors, after=0 sectors
State : clean
Device UUID : dba1b29b:4dc661da:a0fa8289:77f16512
Update Time : Sun May 5 18:53:39 2019
Bad Block Log : 512 entries available at offset 8 sectors
Checksum : eb09426c - correct
Events : 0
Chunk Size : 512K
Device Role : spare
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
After a reboot :
# mdadm --detail /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Sun May 5 18:53:39 2019
Raid Level : raid0
Raid Devices : 2
Total Devices : 3
Persistence : Superblock is persistent
Update Time : Sun May 5 18:53:39 2019
State : active, FAILED, Not Started
Active Devices : 2
Working Devices : 3
Failed Devices : 0
Spare Devices : 1
Chunk Size : 512K
Consistency Policy : unknown
Name : Camera-PC:0 (local to host Camera-PC)
UUID : e3b954a6:ab381819:0aab441c:e1557ee4
Events : 0
Number Major Minor RaidDevice State
- 0 0 0 removed
- 0 0 1 removed
- 8 81 - spare /dev/sde1
- 8 49 1 sync /dev/sdd1
- 8 33 0 sync /dev/sdc1
# mdadm --manage /dev/md127 --remove /dev/sde1
mdadm: hot removed /dev/sde1 from /dev/md127
# mdadm --detail /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Sun May 5 18:53:39 2019
Raid Level : raid0
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Sun May 5 18:53:39 2019
State : active, FAILED, Not Started
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Chunk Size : 512K
Consistency Policy : unknown
Name : Camera-PC:0 (local to host Camera-PC)
UUID : e3b954a6:ab381819:0aab441c:e1557ee4
Events : 0
Number Major Minor RaidDevice State
- 0 0 0 removed
- 0 0 1 removed
- 8 49 1 sync /dev/sdd1
- 8 33 0 sync /dev/sdc1
Playing mdadm --stop /dev/md127 and assemble it again with /dev/sdc1 and
/dev/sdd1 is fine but the problem is back after reboot.
In fact, the 3rd disk should be reformatted or removed from the computer
for the problem to disappear at reboot. If not, the auto-assemble
mechanism at startup seems to be running this command:
root@Camera-PC:/home/user# mdadm --assemble /dev/md0 /dev/sdc1 /dev/sdd1
/dev/sde1
Which gives the above mdadm --detail result, and the following output :
mdadm: failed to RUN_ARRAY /dev/md0: Invalid argument
I don't know if running the --add command (with nothing more) to a RAID0
array should refuse to run, of if maybe spares members into a RAID0
array shouldn't be causing this problem?
In case this feedback is useful.
Julien
