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Volume Degraded after replacing 2 of 4 disks
HI, I am in the process of upgrading my 4* 1TB disks to 4TB each. I replaced disks 4 and 3 without any issue, but when I came to replace number 2 the harddrive was faulty and the resync would ...
Fletch360 wrote:
That is exactly what you need to do - replace disk2 with a 4 TB drive.
When you vertically expand (by upgrading to larger disks), the NAS creates a new RAID group that uses the extra space on the larger disks. That RAID group is concatenated with the original group(s) to create the larger volume.
In your case, the original volume is data-0 (also known as md126). You can see at the top that md126 is RAID-5 and has all 4 disks in the array.
md126 : active raid5 sda3[4] sdd3[3] sdc3[6] sdb3[5] 2915732352 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4] [UUUU]This raid group is 4x1TB.
The new raid group is data-1 (also known as md127). This is also RAID-5, but has only two disks in the array. That new RAID group is therefore degraded.
md127 : active raid5 sdb4[0] sda4[1] 5860253824 blocks super 1.2 level 5, 64k chunk, algorithm 2 [3/2] [UU_]After the first two disks were upgraded, md127 was RAID-1, with only two disks. When you inserted the third disk, the system started expand - converting the group to RAID-5. But that failed. So you are left with a degraded RAID group.
While if you know how, you can fix this with ssh. But it would simpler to just try again with a working disk. When you are done, md127 will be 4x3TB.
FWIW, md0 is the OS partition (which is what the NAS boots from). md1 is the swap partition - and there is something off with that: it is missing sdc3. I don't think that is critical (since it is only swap), but it is odd.
Fletch360 wrote:
That is exactly what you need to do - replace disk2 with a 4 TB drive.
When you vertically expand (by upgrading to larger disks), the NAS creates a new RAID group that uses the extra space on the larger disks. That RAID group is concatenated with the original group(s) to create the larger volume.
In your case, the original volume is data-0 (also known as md126). You can see at the top that md126 is RAID-5 and has all 4 disks in the array.
md126 : active raid5 sda3[4] sdd3[3] sdc3[6] sdb3[5]
2915732352 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
This raid group is 4x1TB.
The new raid group is data-1 (also known as md127). This is also RAID-5, but has only two disks in the array. That new RAID group is therefore degraded.
md127 : active raid5 sdb4[0] sda4[1]
5860253824 blocks super 1.2 level 5, 64k chunk, algorithm 2 [3/2] [UU_]
After the first two disks were upgraded, md127 was RAID-1, with only two disks. When you inserted the third disk, the system started expand - converting the group to RAID-5. But that failed. So you are left with a degraded RAID group.
While if you know how, you can fix this with ssh. But it would simpler to just try again with a working disk. When you are done, md127 will be 4x3TB.
FWIW, md0 is the OS partition (which is what the NAS boots from). md1 is the swap partition - and there is something off with that: it is missing sdc3. I don't think that is critical (since it is only swap), but it is odd.
That's great, Thanks Stephen I will do that now and keep my fingers crossed this disk is better than the last one.
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