Hi, I have a RAID 5 composed by 4x 500Go hdd but for some days, it's 'inactive'. I'm not raid expert and I prefer asking before doing an unrecoverable mistake... Is it possible to fix this raid (md126)? Is it possible to recover data on it? Do I have a disk to change or it's "just" a desynchronization between disks? Thanks for your help # mdadm --version mdadm - v3.3.2 - 21st August 2014 Linux Kernel: 3.18.2-2 # cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md127 : active raid5 sdd2[2] sde2[1] sdc2[0] sdb2[3] 16530624 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU] md126 : inactive sde3[1](S) sdd3[4](S) sdc3[0](S) sdb3[3](S) 1929888000 blocks unused devices: <none> # mdadm --examine /dev/sd[a-z]3 mdadm: No md superblock detected on /dev/sda3. /dev/sdb3: Magic : a92b4efc Version : 0.90.00 UUID : 3327f442:a00b59b2:1397f3c2:236c0edf Creation Time : Tue Jan 27 13:03:52 2009 Raid Level : raid5 Used Dev Size : 482472000 (460.12 GiB 494.05 GB) Array Size : 1447416000 (1380.36 GiB 1482.15 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 126 Update Time : Wed Jan 21 20:55:48 2015 State : active Active Devices : 3 Working Devices : 4 Failed Devices : 1 Spare Devices : 1 Checksum : 6e656c69 - correct Events : 49656 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 3 8 19 3 active sync /dev/sdb3 0 0 8 35 0 active sync /dev/sdc3 1 1 8 67 1 active sync /dev/sde3 2 2 0 0 2 faulty removed 3 3 8 19 3 active sync /dev/sdb3 4 4 8 51 4 spare /dev/sdd3 /dev/sdc3: Magic : a92b4efc Version : 0.90.00 UUID : 3327f442:a00b59b2:1397f3c2:236c0edf Creation Time : Tue Jan 27 13:03:52 2009 Raid Level : raid5 Used Dev Size : 482472000 (460.12 GiB 494.05 GB) Array Size : 1447416000 (1380.36 GiB 1482.15 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 126 Update Time : Wed Jan 21 23:34:52 2015 State : clean Active Devices : 2 Working Devices : 3 Failed Devices : 2 Spare Devices : 1 Checksum : 6e6653d5 - correct Events : 49666 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 0 8 35 0 active sync /dev/sdc3 0 0 8 35 0 active sync /dev/sdc3 1 1 8 67 1 active sync /dev/sde3 2 2 0 0 2 faulty removed 3 3 0 0 3 faulty removed 4 4 8 51 4 spare /dev/sdd3 /dev/sdd3: Magic : a92b4efc Version : 0.90.00 UUID : 3327f442:a00b59b2:1397f3c2:236c0edf Creation Time : Tue Jan 27 13:03:52 2009 Raid Level : raid5 Used Dev Size : 482472000 (460.12 GiB 494.05 GB) Array Size : 1447416000 (1380.36 GiB 1482.15 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 126 Update Time : Wed Jan 21 23:34:52 2015 State : clean Active Devices : 2 Working Devices : 3 Failed Devices : 2 Spare Devices : 1 Checksum : 6e6653e7 - correct Events : 49666 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 4 8 51 4 spare /dev/sdd3 0 0 8 35 0 active sync /dev/sdc3 1 1 8 67 1 active sync /dev/sde3 2 2 0 0 2 faulty removed 3 3 0 0 3 faulty removed 4 4 8 51 4 spare /dev/sdd3 /dev/sde3: Magic : a92b4efc Version : 0.90.00 UUID : 3327f442:a00b59b2:1397f3c2:236c0edf Creation Time : Tue Jan 27 13:03:52 2009 Raid Level : raid5 Used Dev Size : 482472000 (460.12 GiB 494.05 GB) Array Size : 1447416000 (1380.36 GiB 1482.15 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 126 Update Time : Wed Jan 21 23:34:52 2015 State : clean Active Devices : 2 Working Devices : 3 Failed Devices : 2 Spare Devices : 1 Checksum : 6e6653f7 - correct Events : 49666 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 1 8 67 1 active sync /dev/sde3 0 0 8 35 0 active sync /dev/sdc3 1 1 8 67 1 active sync /dev/sde3 2 2 0 0 2 faulty removed 3 3 0 0 3 faulty removed 4 4 8 51 4 spare /dev/sdd3 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html