Hi everyone,
I have almost the same problem as on this old thread : RAID 5 Missing - need help for rebuild
But before I do anything, I would like your confirmation on how to proceed and avoid losing all my data (last backup of my raid was ... 2 months ago - sorry I was in exam period 
)
blkid:
Code
/dev/nvme0n1p1: UUID="2f06c183-22cc-45c8-8b52-3440151c21b6" TYPE="ext4" PARTUUID="956352e9-01"
/dev/nvme0n1p5: UUID="7ff88d8d-4f25-45b2-b5bd-07195cd7b0a0" TYPE="swap" PARTUUID="956352e9-05"
/dev/sdc: UUID="a575048e-f8f1-a8ec-a13c-3eb32d101c88" UUID_SUB="dc9a3685-a540-1c37-51e4-1c8601362b80" LABEL="NAS-V4:Raid5" TYPE="linux_raid_member"
/dev/sdb: UUID="a575048e-f8f1-a8ec-a13c-3eb32d101c88" UUID_SUB="bc41b039-e27b-2ad1-b440-2ab6ddec9dc5" LABEL="NAS-V4:Raid5" TYPE="linux_raid_member"
/dev/sda: UUID="a575048e-f8f1-a8ec-a13c-3eb32d101c88" UUID_SUB="44573f27-06e9-ffb8-5cff-2a53a8ae65e3" LABEL="NAS-V4:Raid5" TYPE="linux_raid_member"
/dev/nvme0n1: PTUUID="956352e9" PTTYPE="dos"cat /proc/mdstat :
Code
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : inactive sdc[2](S) sda[0](S) sdb[1](S)
11720662536 blocks super 1.2
unused devices: <none>mdadm --detail /dev/md0 :
Code
/dev/md0:
Version : 1.2
Raid Level : raid0
Total Devices : 3
Persistence : Superblock is persistent
State : inactive
Name : NAS-V4:Raid5 (local to host NAS-V4)
UUID : a575048e:f8f1a8ec:a13c3eb3:2d101c88
Events : 9490
Number Major Minor RaidDevice
- 8 32 - /dev/sdc
- 8 0 - /dev/sda
- 8 16 - /dev/sdbmdadm --examine /dev/sda :
mdadm --examine /dev/sdb :
mdadm --examine /dev/sdc : last line, I dont understand why there is 2 "." (missing) in Array State
Code
/dev/sdc:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : a575048e:f8f1a8ec:a13c3eb3:2d101c88
Name : NAS-V4:Raid5 (local to host NAS-V4)
Creation Time : Tue Feb 16 12:50:01 2021
Raid Level : raid5
Raid Devices : 3
Avail Dev Size : 7813775024 (3725.90 GiB 4000.65 GB)
Array Size : 7813774336 (7451.80 GiB 8001.30 GB)
Used Dev Size : 7813774336 (3725.90 GiB 4000.65 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=262056 sectors, after=688 sectors
State : clean
Device UUID : dc9a3685:a5401c37:51e41c86:01362b80
Internal Bitmap : 8 sectors from superblock
Update Time : Wed Dec 8 22:49:44 2021
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 3c2156d5 - correct
Events : 9490
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 2
Array State : ..A ('A' == active, '.' == missing, 'R' == replacing)I thought I would just do :
mdadm --stop /dev/md0
then
mdadm --assemble --force --verbose /dev/md0 /dev/sd[abc]
I'd like your confirmation as it concerns data I dont wont to lose 
.
Am I good ?
! Any idea why this happened?
