Hi Leslie, thanks for your suggestion! I succeeded to do it, although the path was a bit longer: a) remove logical volume (synology creates one, it prevents stopping the array): # ll /dev/mapper/ crw------- 1 root root 10, 59 Sep 5 2020 control brw------- 1 root root 253, 0 Jun 10 11:57 vol1-origin # dmsetup remove vol1-origin b) stop the array: # mdadm --stop /dev/md2 mdadm: stopped /dev/md2 c) recreate the array with the original layout: # mdadm --verbose --create /dev/md2 --chunk=64 --level=6 --raid-devices=5 --metadata=1.2 /dev/sda3 /dev/sdb3 /dev/sdc3 /dev/sdd3 /dev/sde3 mdadm: layout defaults to left-symmetric mdadm: layout defaults to left-symmetric mdadm: layout defaults to left-symmetric mdadm: /dev/sda3 appears to be part of a raid array: level=raid6 devices=5 ctime=Sat Sep 5 12:46:57 2020 mdadm: layout defaults to left-symmetric mdadm: /dev/sdb3 appears to be part of a raid array: level=raid6 devices=5 ctime=Sat Sep 5 12:46:57 2020 mdadm: layout defaults to left-symmetric mdadm: /dev/sdc3 appears to be part of a raid array: level=raid6 devices=5 ctime=Sat Sep 5 12:46:57 2020 mdadm: layout defaults to left-symmetric mdadm: /dev/sdd3 appears to be part of a raid array: level=raid6 devices=5 ctime=Sat Sep 5 12:46:57 2020 mdadm: layout defaults to left-symmetric mdadm: /dev/sde3 appears to be part of a raid array: level=raid6 devices=5 ctime=Sat Sep 5 12:46:57 2020 mdadm: size set to 2925544256K Continue creating array? yes mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md2 started. d) checking it: # cat /proc/mdstat Personalities : [raid1] [linear] [raid0] [raid10] [raid6] [raid5] [raid4] md2 : active raid6 sde3[4] sdd3[3] sdc3[2] sdb3[1] sda3[0] 8776632768 blocks super 1.2 level 6, 64k chunk, algorithm 2 [5/5] [UUUUU] [=>...................] resync = 6.8% (199953972/2925544256) finish=2440.4min speed=18613K/sec md1 : active raid1 sda2[1] sdb2[2] sdc2[3] sdd2[0] sde2[4] 2097088 blocks [5/5] [UUUUU] md0 : active raid1 sdc1[3] sdd1[0] sde1[4] 2490176 blocks [5/3] [U__UU] unused devices: <none> After that, I fsck'ed and mounted it read-only, and now I'm happy recovering my data... :-) Thanks again! Carlos Em 14/06/2021 22:36, Leslie Rhorer escreveu: > Oops! 'Sorry. That should be: > > mdadm -S /dev/md2 > mdadm -C -f -e 1.2 -n 5 -c 64K --level=6 -p left-symmetric /dev/md2 > /dev/sda3 /dev/sdb3 /dev/sdc3 /dev/sdd3 /dev/sde3 > > > You only have five disks, not six. >
