NotAnExpert

Thanks!
 
Ran the commands, the non-forced assembly failed but the forced fixed the issue. I have been checking files and folders and have not found anything wrong yet.
 
Appreciate your help and detailed instructions!
 
mdadm --stop /dev/md0
mdadm: stopped /dev/md0
 
 
mdadm /dev/md0 --assemble /dev/sd[abcde]
mdadm: /dev/md0 assembled from 2 drives - not enough to start the array
 
 
mdadm /dev/md0 --assemble --force /dev/sd[abcde]
mdadm: forcing event count in /dev/sdb(1) from 26341 upto 26352
mdadm: forcing event count in /dev/sdd(3) from 26341 upto 26352
mdadm: forcing event count in /dev/sde(4) from 26341 upto 26352
mdadm: clearing FAULTY flag for device 3 in /dev/md0 for /dev/sdd
mdadm: clearing FAULTY flag for device 4 in /dev/md0 for /dev/sde
mdadm: Marking array /dev/md0 as 'clean'
mdadm: /dev/md0 has been started with 5 drives.
 
cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active (auto-read-only) raid6 sda[0] sde[4] sdd[3] sdc[2] sdb[1]
      35156259840 blocks super 1.2 level 6, 512k chunk, algorithm 2 [5/5] [UUUUU]
      bitmap: 0/88 pages [0KB], 65536KB chunk
 
unused devices: <none>
 
mdadm -D /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Nov  5 22:00:27 2020
        Raid Level : raid6
        Array Size : 35156259840 (33527.62 GiB 36000.01 GB)
     Used Dev Size : 11718753280 (11175.87 GiB 12000.00 GB)
      Raid Devices : 5
     Total Devices : 5
       Persistence : Superblock is persistent
 
     Intent Bitmap : Internal
 
       Update Time : Thu Nov 26 07:13:29 2020
             State : clean
    Active Devices : 5
   Working Devices : 5
    Failed Devices : 0
     Spare Devices : 0
 
            Layout : left-symmetric
        Chunk Size : 512K
 
Consistency Policy : bitmap
 
              Name : helios64:0  (local to host helios64)
              UUID : f2188013:e3cdc6dd:c8a55f0d:d0e9c602
            Events : 26352
 
    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       8       16        1      active sync   /dev/sdb
       2       8       32        2      active sync   /dev/sdc
       3       8       48        3      active sync   /dev/sdd
       4       8       64        4      active sync   /dev/sde
 
=============================================================
 
After running commands I went back to OMV web UI and raid was listed with clean state.
 
Under filesystem I selected the raid6 “data” and mounted it.
 
Added shares to Samba and all data is accessible.
 

Thanks!
 
Ran the commands, the non-forced assembly failed but the forced fixed the issue. I have been checking files and folders and have not found anything wrong yet.
 
Appreciate your help and detailed instructions!
 
mdadm --stop /dev/md0
mdadm: stopped /dev/md0
 
 
mdadm /dev/md0 --assemble /dev/sd[abcde]
mdadm: /dev/md0 assembled from 2 drives - not enough to start the array
 
 
mdadm /dev/md0 --assemble --force /dev/sd[abcde]
mdadm: forcing event count in /dev/sdb(1) from 26341 upto 26352
mdadm: forcing event count in /dev/sdd(3) from 26341 upto 26352
mdadm: forcing event count in /dev/sde(4) from 26341 upto 26352
mdadm: clearing FAULTY flag for device 3 in /dev/md0 for /dev/sdd
mdadm: clearing FAULTY flag for device 4 in /dev/md0 for /dev/sde
mdadm: Marking array /dev/md0 as 'clean'
mdadm: /dev/md0 has been started with 5 drives.
 
cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active (auto-read-only) raid6 sda[0] sde[4] sdd[3] sdc[2] sdb[1]
      35156259840 blocks super 1.2 level 6, 512k chunk, algorithm 2 [5/5] [UUUUU]
      bitmap: 0/88 pages [0KB], 65536KB chunk
 
unused devices: <none>
 
mdadm -D /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Nov  5 22:00:27 2020
        Raid Level : raid6
        Array Size : 35156259840 (33527.62 GiB 36000.01 GB)
     Used Dev Size : 11718753280 (11175.87 GiB 12000.00 GB)
      Raid Devices : 5
     Total Devices : 5
       Persistence : Superblock is persistent
 
     Intent Bitmap : Internal
 
       Update Time : Thu Nov 26 07:13:29 2020
             State : clean
    Active Devices : 5
   Working Devices : 5
    Failed Devices : 0
     Spare Devices : 0
 
            Layout : left-symmetric
        Chunk Size : 512K
 
Consistency Policy : bitmap
 
              Name : helios64:0  (local to host helios64)
              UUID : f2188013:e3cdc6dd:c8a55f0d:d0e9c602
            Events : 26352
 
    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       8       16        1      active sync   /dev/sdb
       2       8       32        2      active sync   /dev/sdc
       3       8       48        3      active sync   /dev/sdd
       4       8       64        4      active sync   /dev/sde
 
=============================================================
 
After running commands I went back to OMV web UI and raid was listed with clean state.
 
Under filesystem I selected the raid6 “data” and mounted it.
 
Added shares to Samba and all data is accessible.
 

At first glance, things look pretty good so it should be easy reassemble the array.
 
The reason it didn' t happen automatically it's because the event count between sda, sdc is different from sdb, sdd, sde. Fortunately the difference is very small, so data on the RAID should still be ok.
 
First you need to stop the array
 
mdadm --stop /dev/md0
 
Let's try to re assemble without --force option
 
mdadm /dev/md0 --assemble /dev/sd[abcde]
 
Let us know if it works. If yes then you array should start the syncing process (cat /prod/mdstat), you could share the output of mdadm -D /dev/md0
 
If if fails, please show the output. Next step, if previous one failed, it's to try assemble with --force option.  Please take note that if --force is used you might end up with few file corrupted (whatever writing operation that happen in the difference of event count, in your case the difference of event count is very small).
 
mdadm /dev/md0 --assemble --force /dev/sd[abcde]
 
Same here, share output of cat /prod/mdstat and mdadm -D /dev/md0

This is the output:
 
mdadm --examine /dev/sd[abcde]
 
/dev/sda:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x1
     Array UUID : f2188013:e3cdc6dd:c8a55f0d:d0e9c602
           Name : helios64:0  (local to host helios64)
  Creation Time : Thu Nov  5 22:00:27 2020
     Raid Level : raid6
   Raid Devices : 5
 
Avail Dev Size : 23437506560 (11175.87 GiB 12000.00 GB)
     Array Size : 35156259840 (33527.62 GiB 36000.01 GB)
    Data Offset : 264192 sectors
   Super Offset : 8 sectors
   Unused Space : before=264112 sectors, after=0 sectors
          State : clean
    Device UUID : ae15b2cf:d55f6fcf:1e4ef3c5:1824b2c7
 
Internal Bitmap : 8 sectors from superblock
    Update Time : Thu Nov 26 07:13:29 2020
  Bad Block Log : 512 entries available at offset 56 sectors
       Checksum : 1e6baa82 - correct
         Events : 26352
 
         Layout : left-symmetric
     Chunk Size : 512K
 
   Device Role : Active device 0
   Array State : AAA.. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x1
     Array UUID : f2188013:e3cdc6dd:c8a55f0d:d0e9c602
           Name : helios64:0  (local to host helios64)
  Creation Time : Thu Nov  5 22:00:27 2020
     Raid Level : raid6
   Raid Devices : 5
 
Avail Dev Size : 23437506560 (11175.87 GiB 12000.00 GB)
     Array Size : 35156259840 (33527.62 GiB 36000.01 GB)
    Data Offset : 264192 sectors
   Super Offset : 8 sectors
   Unused Space : before=264112 sectors, after=0 sectors
          State : clean
    Device UUID : e6c4d356:a1021369:2fcd3661:deaa4406
 
Internal Bitmap : 8 sectors from superblock
    Update Time : Wed Nov 25 23:33:03 2020
  Bad Block Log : 512 entries available at offset 56 sectors
       Checksum : 1909966b - correct
         Events : 26341
 
         Layout : left-symmetric
     Chunk Size : 512K
 
   Device Role : Active device 1
   Array State : AAAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdc:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x1
     Array UUID : f2188013:e3cdc6dd:c8a55f0d:d0e9c602
           Name : helios64:0  (local to host helios64)
  Creation Time : Thu Nov  5 22:00:27 2020
     Raid Level : raid6
   Raid Devices : 5
 
Avail Dev Size : 23437506560 (11175.87 GiB 12000.00 GB)
     Array Size : 35156259840 (33527.62 GiB 36000.01 GB)
    Data Offset : 264192 sectors
   Super Offset : 8 sectors
   Unused Space : before=264112 sectors, after=0 sectors
          State : clean
    Device UUID : 31f197dd:6f6d0545:fbc627a6:53582fd4
 
Internal Bitmap : 8 sectors from superblock
    Update Time : Thu Nov 26 07:13:29 2020
  Bad Block Log : 512 entries available at offset 56 sectors
       Checksum : 8e9940b8 - correct
         Events : 26352
 
         Layout : left-symmetric
     Chunk Size : 512K
 
   Device Role : Active device 2
   Array State : AAA.. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x1
     Array UUID : f2188013:e3cdc6dd:c8a55f0d:d0e9c602
           Name : helios64:0  (local to host helios64)
  Creation Time : Thu Nov  5 22:00:27 2020
     Raid Level : raid6
   Raid Devices : 5
 
Avail Dev Size : 23437506560 (11175.87 GiB 12000.00 GB)
     Array Size : 35156259840 (33527.62 GiB 36000.01 GB)
    Data Offset : 264192 sectors
   Super Offset : 8 sectors
   Unused Space : before=264112 sectors, after=0 sectors
          State : clean
    Device UUID : 3296b043:2025da1d:edc6e9eb:99e57e34
 
Internal Bitmap : 8 sectors from superblock
    Update Time : Wed Nov 25 23:33:03 2020
  Bad Block Log : 512 entries available at offset 56 sectors
       Checksum : 739abeb1 - correct
         Events : 26341
 
         Layout : left-symmetric
     Chunk Size : 512K
 
   Device Role : Active device 3
   Array State : AAAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sde:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x1
     Array UUID : f2188013:e3cdc6dd:c8a55f0d:d0e9c602
           Name : helios64:0  (local to host helios64)
  Creation Time : Thu Nov  5 22:00:27 2020
     Raid Level : raid6
   Raid Devices : 5
 
Avail Dev Size : 23437506560 (11175.87 GiB 12000.00 GB)
     Array Size : 35156259840 (33527.62 GiB 36000.01 GB)
    Data Offset : 264192 sectors
   Super Offset : 8 sectors
   Unused Space : before=264112 sectors, after=0 sectors
          State : clean
    Device UUID : ecf702ec:8dec71e2:a7f465fa:86b78694
 
Internal Bitmap : 8 sectors from superblock
    Update Time : Wed Nov 25 23:33:03 2020
  Bad Block Log : 512 entries available at offset 56 sectors
       Checksum : 4f08e782 - correct
         Events : 26341
 
         Layout : left-symmetric
     Chunk Size : 512K
 
   Device Role : Active device 4
   Array State : AAAAA ('A' == active, '.' == missing, 'R' == replacing)
 
=======
 
Regarding what I tried
 
When I noticed I couldn’t access the files and folders on my computer I tried other computers. Then I went to OMV front end and changed the workgroup thinking it was just a Windows issue and when that didn’t work I removed the shares from Samba, did not delete them from Access Right Management > Shared Folders.
 
At that point I realized the filesystem was missing and mounting was disabled. I did nothing else either in OPV web interface or through SSH commands except for the info and commands you have requested.
 
Thank you!