On Wed, Jan 08, 2020 at 10:31:28AM +0100, Marco Heiming wrote:
> So here is what what it looked like at the time it was working:
>
> mdadm -D /dev/md0
> /dev/md0:
> Creation Time : Wed Jan 7 18:14:37 2015
> Raid Level : raid5
> Array Size : 5860270080 (5588.79 GiB 6000.92 GB)
> Used Dev Size : 2930135040 (2794.39 GiB 3000.46 GB)
> Raid Devices : 3
> Total Devices : 4
A three disk raid5 with spare (odd, why not raid6 then?)
> Somehow the spare was not activated and so the array degraded was inactive.
>
> I activated the spare and the array was syncing.
Then something went wrong in this step.
It seems like you did something else.
> mdadm --examine /dev/sd[b-z]
> /dev/sdb:
> Creation Time : Wed Jan 7 18:14:37 2015
> Raid Level : raid5
> Raid Devices : 4
>
> Avail Dev Size : 5860274096 (2794.40 GiB 3000.46 GB)
> Array Size : 8790405120 (8383.18 GiB 9001.37 GB)
> Used Dev Size : 5860270080 (2794.39 GiB 3000.46 GB)
For whatever reason, it's a 4 disk raid5 now.
Array size went up from 6000GB to 9000GB accordingly.
> Device Role : Active device 1
> Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
And one disk is missing so no redundancy here.
> When i try to assemble the array with the two (hopefully) fine drives it fails:
You can't assemble a 4 disk raid5 with only 2 drives.
Your examine also only gave two disks out of 4.
You need 3 drives with good data on them, and a 4th drive to restore redundancy.
Whether you have those 3 drives, only you yourself know...
Regards
Andreas Klauer
