wiki:raid_troubleshooting
Table of Contents
RAID troubleshooting
Inactive raid 5
All disks shown as spares (S):
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rpi5:~# cat /proc/mdstat Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : inactive sdd[3](S) sda[0](S) sdc[2](S) sdb[1](S) sde[5](S) 19534432440 blocks super 1.2
Try reassembling the array
mdadm -A /dev/md0
If you now have a “removed” state for one of the disks, you can readd it again, just make sure you zero-out the superblock on the correct drive:
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rpi5:~# mdadm --detail /dev/md0 /dev/md0: Version : 1.2 Creation Time : Sun Aug 10 19:13:14 2025 Raid Level : raid5 Array Size : 15627544576 (14.55 TiB 16.00 TB) Used Dev Size : 3906886144 (3.64 TiB 4.00 TB) Raid Devices : 5 Total Devices : 4 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Thu Jun 25 17:08:05 2026 State : clean, degraded Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Consistency Policy : bitmap Name : rpi5:0 (local to host rpi5) UUID : de8f9a7f:cc5ac2f5:9b57796e:5fd178cf Events : 30495 Number Major Minor RaidDevice State - 0 0 0 removed 1 8 16 1 active sync /dev/sdb 2 8 32 2 active sync /dev/sdc 3 8 48 3 active sync /dev/sdd 5 8 64 4 active sync /dev/sde rpi5:~# ls /dev/sd* /dev/sda /dev/sdb /dev/sdc /dev/sdd /dev/sde rpi5:~# mdadm --zero-superblock /dev/sda rpi5:~# mdadm /dev/md0 --add /dev/sda mdadm: added /dev/sda rpi5:~# mdadm --detail /dev/md0 /dev/md0: Version : 1.2 Creation Time : Sun Aug 10 19:13:14 2025 Raid Level : raid5 Array Size : 15627544576 (14.55 TiB 16.00 TB) Used Dev Size : 3906886144 (3.64 TiB 4.00 TB) Raid Devices : 5 Total Devices : 5 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Thu Jun 25 17:17:34 2026 State : clean, degraded, recovering Active Devices : 4 Working Devices : 5 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric Chunk Size : 512K Consistency Policy : bitmap Rebuild Status : 0% complete Name : rpi5:0 (local to host rpi5) UUID : de8f9a7f:cc5ac2f5:9b57796e:5fd178cf Events : 30497 Number Major Minor RaidDevice State 6 8 0 0 spare rebuilding /dev/sda 1 8 16 1 active sync /dev/sdb 2 8 32 2 active sync /dev/sdc 3 8 48 3 active sync /dev/sdd 5 8 64 4 active sync /dev/sde
Tested on
See also
References
wiki/raid_troubleshooting.txt · Last modified: by antisa