Help recovering a raid5 array

A little bit of background first. I store a bunch of data on a Thecus N4200Pro NAS array. I had gotten a report that one of the 4 drives in the array was showing smart errors. - So I swapped out the offending drive (#4) and it got to work rebuilding. About 60% into the rebuild one of the other drives in the array drops out, #1 in this case. - Great.. I shut down and try swapping back in the original #4 to see if it will come back up. No dice. - So I shut down and swap #1 & #2 to see if they can recover with the bad drive swapped around and replace the #4 with the half-rebuilt #4. In hindsight this was bad. I should have shut down after the first one and cloned all the original discs from there. - The device boots back up and of course the raid fails to assemble, showing only discs 3 and 4, 4 being marked as a spare. - At this point I shut everything down and pull all the discs and clone them, making sure to keep track of the number order. - I put all 4 cloned discs into my unbutu 16.04 LTS box in the correct drive order and booted up. - All 4 discs show up, and show the partitions in Disks. It shows a raid5 array and a raid1 array as well. The raid1 array is the system info for the NAS, not really concerned with that. The raid5 array is the one I'm interested in with all my data on it, but I can't access anything on it. So time to start digging. First I ran cat /proc/mdstat to see the arrays- jake@ubuntu-box:~$ cat /proc/mdstat Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sdd1 1959884 blocks super 1.0 [4/1] [___U] md1 : inactive sdd2(S) sdc2(S) sdb2(S) sda2(S) 3899202560 blocks unused devices: Ok, sees two arrays. So we get the details on md1 from: mdadm --detail /dev/md1 jake@ubuntu-box:~$ sudo mdadm --detail /dev/md1 /dev/md1: Version : 0.90 Raid Level : raid0 Total Devices : 4 Preferred Minor : 0 Persistence : Superblock is persistent State : inactive UUID : e7ab07c3:b9ffa9ae:377e3cd3:a8ece374 Events : 0.14344 Number Major Minor RaidDevice - 8 50 - /dev/sdd2 - 8 34 - /dev/sdc2 - 8 18 - /dev/sdb2 - 8 2 - /dev/sda2[/CODE] Hrmm.. that's odd. showing the raid as raid0, which is not the case. Ok, lets check out each individual partition with: mdadm --examine /dev/sdXX Disc 1 jake@ubuntu-box:~$ sudo mdadm --examine /dev/sda2/ dev/sda2: Magic : a92b4efc Version : 0.90.00 UUID : e7ab07c3:b9ffa9ae:377e3cd3:a8ece374 Creation Time : Thu Aug 18 14:30:36 2011 Raid Level : raid5 Used Dev Size : 974800000 (929.64 GiB 998.20 GB) Array Size : 2924400000 (2788.93 GiB 2994.59 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Update Time : Tue Mar 13 14:00:33 2018 State : clean Active Devices : 3 Working Devices : 4 Failed Devices : 1 Spare Devices : 1 Checksum : e52c5f8 - correct Events : 20364 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 0 8 2 0 active sync /dev/sda2 0 0 8 2 0 active sync /dev/sda2 1 1 8 18 1 active sync /dev/sdb2 2 2 8 34 2 active sync /dev/sdc2 3 3 0 0 3 faulty removed 4 4 8 50 4 spare /dev/sdd2 Disc 2 jake@ubuntu-box:~$ sudo mdadm --examine /dev/sdb2/ dev/sdb2: Magic : a92b4efc Version : 0.90.00 UUID : e7ab07c3:b9ffa9ae:377e3cd3:a8ece374 Creation Time : Thu Aug 18 14:30:36 2011 Raid Level : raid5 Used Dev Size : 974800000 (929.64 GiB 998.20 GB) Array Size : 2924400000 (2788.93 GiB 2994.59 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Update Time : Tue Mar 13 14:56:30 2018 State : clean Active Devices : 2 Working Devices : 3 Failed Devices : 1 Spare Devices : 1 Checksum : e597e42 - correct Events : 238868 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 1 8 18 1 active sync /dev/sdb2 0 0 0 0 0 removed 1 1 8 18 1 active sync /dev/sdb2 2 2 8 34 2 active sync /dev/sdc2 3 3 0 0 3 faulty removed 4 4 8 50 4 spare /dev/sdd2 Disc 3 jake@ubuntu-box:~$ sudo mdadm --examine /dev/sdc2/ dev/sdc2: Magic : a92b4efc Version : 0.90.00 UUID : e7ab07c3:b9ffa9ae:377e3cd3:a8ece374 Creation Time : Thu Aug 18 14:30:36 2011 Raid Level : raid5 Used Dev Size : 974800000 (929.64 GiB 998.20 GB) Array Size : 2924400000 (2788.93 GiB 2994.59 GB) Raid Devices : 4 Total Devices : 3 Preferred Minor : 1 Update Time : Tue Mar 13 15:10:07 2018 State : clean Active Devices : 1 Working Devices : 2 Failed Devices : 2 Spare Devices : 1 Checksum : e598570 - correct Events : 239374 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 2 8 34 2 active sync /dev/sdc2 0 0 0 0 0 removed 1 1 0 0 1 faulty removed 2 2 8 34 2 active sync /dev/sdc2 3 3 0 0 3 faulty removed 4 4 8 50 4 spare /dev/sdd2 and Disc 4 jake@ubuntu-box:~$ sudo mdadm --examine /dev/sdd2/ dev/sdd2: Magic : a92b4efc Version : 0.90.00 UUID : e7ab07c3:b9ffa9ae:377e3cd3:a8ece374 Creation Time : Thu Aug 18 14:30:36 2011 Raid Level : raid5 Used Dev Size : 974800000 (929.64 GiB 998.20 GB) Array Size : 2924400000 (2788.93 GiB 2994.59 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Update Time : Tue Mar 13 11:03:10 2018 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Checksum : e526d87 - correct Events : 14344 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 3 8 50 3 active sync /dev/sdd2 0 0 8 2 0 active sync /dev/sda2 1 1 8 18 1 active sync /dev/sdb2 2 2 8 34 2 active sync /dev/sdc2 3 3 8 50 3 active sync /dev/sdd2 So - Magic numbers and UUID are all good between the set. Events are all out of whack because it had tried to rebuild the replaced #4 as a spare instead of just rebuilding #4 Disc 4 has the correct info for the raid, and the sequencing as it was the drive I pulled originally and didn't get anything re-written. Discs 1-3 are showing in various states of chaos from swapping things around. So two questions - 1. Why is it showing up as raid0 in the mdadm --detail 2. Is it possible to update the info for the first three discs that I got from the mdadm --examine /dev/sdd2 so that it sees everything as it should be, instead of the cluster that I inadvertently made of it. I *think* if I can find a way to update the info for those partitions or discs the raid should reassemble correctly and rebuild itself so I can access my data Any ideas would be helpful, as I've gotten about as far as I can get trying to figure this out on my own and doing a ton of searching.