Well, while I was contemplating my options, a power outage caused my
array to fail to a degraded state. One of the drives is now marked as
a spare and i can't figure out how to get it back into the array. Does
it have to be completely rebuilt?
bill@bill-desk:~$ sudo mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sat Sep 22 19:10:10 2018
Raid Level : raid5
Array Size : 23441679360 (22355.73 GiB 24004.28 GB)
Used Dev Size : 7813893120 (7451.91 GiB 8001.43 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Mon Mar 2 17:41:32 2020
State : clean, degraded
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 64K
Consistency Policy : bitmap
Name : bill-desk:0 (local to host bill-desk)
UUID : 06ad8de5:3a7a15ad:88116f44:fcdee150
Events : 10407
Number Major Minor RaidDevice State
0 8 129 0 active sync /dev/sdi1
1 8 145 1 active sync /dev/sdj1
2 8 161 2 active sync /dev/sdk1
- 0 0 3 removed
4 8 177 - spare /dev/sdl1
bill@bill-desk:~$ sudo mdadm --examine /dev/sdi1
/dev/sdi1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x9
Array UUID : 06ad8de5:3a7a15ad:88116f44:fcdee150
Name : bill-desk:0 (local to host bill-desk)
Creation Time : Sat Sep 22 19:10:10 2018
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 15627786240 (7451.91 GiB 8001.43 GB)
Array Size : 23441679360 (22355.73 GiB 24004.28 GB)
Data Offset : 264192 sectors
Super Offset : 8 sectors
Unused Space : before=264112 sectors, after=0 sectors
State : clean
Device UUID : ab1323e0:9c0426cf:3e168733:b73e9c5c
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Mar 2 17:41:16 2020
Bad Block Log : 512 entries available at offset 40 sectors - bad
blocks present.
Checksum : f197b17c - correct
Events : 10407
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 0
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
bill@bill-desk:~$ sudo mdadm --examine /dev/sdj1
/dev/sdj1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 06ad8de5:3a7a15ad:88116f44:fcdee150
Name : bill-desk:0 (local to host bill-desk)
Creation Time : Sat Sep 22 19:10:10 2018
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 15627786240 (7451.91 GiB 8001.43 GB)
Array Size : 23441679360 (22355.73 GiB 24004.28 GB)
Data Offset : 264192 sectors
Super Offset : 8 sectors
Unused Space : before=264112 sectors, after=0 sectors
State : clean
Device UUID : c875f246:ce25d947:a413e198:4100082e
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Mar 2 17:41:32 2020
Bad Block Log : 512 entries available at offset 40 sectors
Checksum : 7e0f516 - correct
Events : 10749
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 1
Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
bill@bill-desk:~$ sudo mdadm --examine /dev/sdk1
/dev/sdk1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 06ad8de5:3a7a15ad:88116f44:fcdee150
Name : bill-desk:0 (local to host bill-desk)
Creation Time : Sat Sep 22 19:10:10 2018
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 15627786240 (7451.91 GiB 8001.43 GB)
Array Size : 23441679360 (22355.73 GiB 24004.28 GB)
Data Offset : 264192 sectors
Super Offset : 8 sectors
Unused Space : before=264112 sectors, after=0 sectors
State : clean
Device UUID : fd0634e6:6943f723:0e30260e:e253b1f4
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Mar 2 17:41:32 2020
Bad Block Log : 512 entries available at offset 40 sectors
Checksum : bf2f13f2 - correct
Events : 10749
Layout : left-symmetric
Chunk Size : 64K
Device Role : Active device 2
Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
bill@bill-desk:~$ sudo mdadm --examine /dev/sdl1
/dev/sdl1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x9
Array UUID : 06ad8de5:3a7a15ad:88116f44:fcdee150
Name : bill-desk:0 (local to host bill-desk)
Creation Time : Sat Sep 22 19:10:10 2018
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 15627786240 (7451.91 GiB 8001.43 GB)
Array Size : 23441679360 (22355.73 GiB 24004.28 GB)
Data Offset : 264192 sectors
Super Offset : 8 sectors
Unused Space : before=264112 sectors, after=0 sectors
State : clean
Device UUID : 8c628aed:802a5dc8:9d8a8910:9794ec02
Internal Bitmap : 8 sectors from superblock
Update Time : Mon Mar 2 17:41:32 2020
Bad Block Log : 512 entries available at offset 40 sectors - bad
blocks present.
Checksum : 7b89f1e6 - correct
Events : 10749
Layout : left-symmetric
Chunk Size : 64K
Device Role : spare
Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
