So step 1, revert the reshape. Step 2, get the array back running.
Step 3, start the reshape again.
root@nas:~# mdadm --readwrite /dev/md0
root@nas:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun May 17 00:23:42 2020
Raid Level : raid5
Array Size : 35156256768 (33527.62 GiB 36000.01 GB)
Used Dev Size : 11718752256 (11175.87 GiB 12000.00 GB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Tue May 26 01:13:08 2020
State : clean
Active Devices : 4
Working Devices : 5
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Consistency Policy : bitmap
Name : nas:0 (local to host nas)
UUID : d7d800b3:d203ff93:9cc2149a:804a1b97
Events : 38605
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
4 8 65 3 active sync /dev/sde1
5 8 81 - spare /dev/sdf1
root@nas:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
[raid4] [raid10]
md0 : active raid5 sda1[0] sdf1[5](S) sde1[4] sdd1[2] sdc1[1]
35156256768 blocks super 1.2 level 5, 512k chunk, algorithm 2
[4/4] [UUUU]
bitmap: 0/88 pages [0KB], 65536KB chunk
unused devices: <none>
=================================
ok, got a bit too scared :)
it´s now working again. so I can plugin a UPS and restart grow.
guys, thank you all very much for your help.
