I found simmilar problem here: Missing mdadm raid5 array reassembles as raid0 after powerout, but mine is a bit different.Here too my raid5 reassembles as raid0, but i don't see any of my devices marked as spare in mdadm -E /dev/sdX1 output: /dev/sdb1:          Magic : a92b4efc        Version : 1.2    Feature Map : 0x0     Array UUID : 9b244d41:0b94c8f7:0da323ac:f2a873ec           Name : bekap:0  (local to host bekap)  Creation Time : Wed Oct  9 16:03:25 2013     Raid Level : raid5   Raid Devices : 3 Avail Dev Size : 5860268032 (2794.39 GiB 3000.46 GB)     Array Size : 5860267008 (5588.79 GiB 6000.91 GB)  Used Dev Size : 5860267008 (2794.39 GiB 3000.46 GB)    Data Offset : 262144 sectors   Super Offset : 8 sectors   Unused Space : before=262064 sectors, after=1024 sectors          State : active    Device UUID : f8405c86:85d8bade:8a74b0f5:fec08e3f    Update Time : Sat Jan 16 04:41:05 2016       Checksum : da1a9cb2 - correct         Events : 134111         Layout : left-symmetric     Chunk Size : 512K   Device Role : Active device 0   Array State : AA. ('A' == active, '.' == missing, 'R' == replacing)/dev/sdc1:          Magic : a92b4efc        Version : 1.2    Feature Map : 0x0     Array UUID : 9b244d41:0b94c8f7:0da323ac:f2a873ec           Name : bekap:0  (local to host bekap)  Creation Time : Wed Oct  9 16:03:25 2013     Raid Level : raid5   Raid Devices : 3 Avail Dev Size : 5860268032 (2794.39 GiB 3000.46 GB)     Array Size : 5860267008 (5588.79 GiB 6000.91 GB)  Used Dev Size : 5860267008 (2794.39 GiB 3000.46 GB)    Data Offset : 262144 sectors   Super Offset : 8 sectors   Unused Space : before=262064 sectors, after=1024 sectors          State : active    Device UUID : d704efde:067523c1:a6de1be2:e752323f    Update Time : Sat Jan 16 04:41:05 2016       Checksum : 124f919 - correct         Events : 134111         Layout : left-symmetric     Chunk Size : 512K   Device Role : Active device 1   Array State : AA. ('A' == active, '.' == missing, 'R' == replacing)/dev/sdd1:          Magic : a92b4efc        Version : 1.2    Feature Map : 0x0     Array UUID : 9b244d41:0b94c8f7:0da323ac:f2a873ec           Name : bekap:0  (local to host bekap)  Creation Time : Wed Oct  9 16:03:25 2013     Raid Level : raid5   Raid Devices : 3 Avail Dev Size : 5860268032 (2794.39 GiB 3000.46 GB)     Array Size : 5860267008 (5588.79 GiB 6000.91 GB)  Used Dev Size : 5860267008 (2794.39 GiB 3000.46 GB)    Data Offset : 262144 sectors   Super Offset : 8 sectors   Unused Space : before=262064 sectors, after=1024 sectors          State : clean    Device UUID : c52383f7:910118d3:e808a29f:b4edad2c    Update Time : Mon Dec 28 10:46:40 2015       Checksum : d69974b5 - correct         Events : 52676         Layout : left-symmetric     Chunk Size : 512K   Device Role : Active device 2   Array State : AAA ('A' == active, '.' == missing, 'R' == replacing)But they are marked as S (which as far as I know stands for spare) in /proc/mdstat (and there are no personalities for md0):Personalities : md0 : inactive sdb1[0](S) sdd1[3](S) sdc1[1](S)      8790402048 blocks super 1.2unused devices: <none>Here is mdadm -D /dev/md0 output:/dev/md0:        Version : 1.2     Raid Level : raid0  Total Devices : 3    Persistence : Superblock is persistent          State : inactive           Name : bekap:0  (local to host bekap)           UUID : 9b244d41:0b94c8f7:0da323ac:f2a873ec         Events : 134111    Number   Major   Minor   RaidDevice       -       8       17        -        /dev/sdb1       -       8       33        -        /dev/sdc1       -       8       49        -        /dev/sdd1So I'm a bit confused why it can't reassemble this array if it has two (I would say good devices) out of three. I'm not sure if mdadm -D /dev/md0 showed it as raid0 since the failure or if I just messed it up while trying to reassemble the array (I tried mdadm --stop /dev/md0 and mdadm --assemble --scan --verbose and mdadm --assemble --scan --verbose /dev/md0 /dev/sdb1 /dev/sdc1 or something simmilar - I can try to get exact commands if it is necessary).So, my question: can I remove sdd1 from array, then assemble md0 without it and then add sdd1 again? Or should I use --assemble --force --run as mentioned in the linked question? Or something else? I'm quite unexperienced with linux raid and mdadm. Thanks a lot.
raid5 array reassembles as raid0
mdadm;software raid;raid5;raid0
Ok, just to conclude this - basically, what was said in that link helped, here are my exact commands: mdadm --assemble --force /dev/md0 /dev/sdb1 /dev/sdc1mdadm --add /dev/md0 /dev/sdd1 (--re-add didn't work), after this it started resyncing - took about 20 hoursThen, since there is lvm over:lvchange -ay data/datafsck /dev/data/dataThanks for help.