RN104 degraded, but no prorgess

Hi all.

I am using my RN104 as a backup device sonce a very, very long time w/o any issues... Cool thing, not high performance, but good it works :-).

I changed in my RN104 one of the 4 harddrives. Before I had 4x 4TB WD red harddrives. I exchanged a old one some days/weeks ago (regular exchange without failiure). Now I have the following setup:

1x WD80EFBX; 2x WD60EFAX; 1x WD60EFRX

The front display shows "DEGRADED" error message - same on the web frontend, but no progress.

"green" traffic light on all 4 devices

mdadm --detail /dev/md127 shows "degraded", but I do not know why and I have no idea how that happend (is ithis normal) or any idea how to fix that?

Any proposal is welcome :smileyhappy:,

Thanks. Norbert

checking /proc/mdstat shows no progress:

Personalities : [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md126 : active raid5 sda3[5] sdc3[3] sdd3[6] sdb3[4]
11706503424 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

md127 : active raid5 sdc4[1] sda4[3] sdb4[2]
5860115712 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/3] [_UUU]

md1 : active raid10 sda2[0] sdd2[3] sdc2[2] sdb2[1]
1044480 blocks super 1.2 512K chunks 2 near-copies [4/4] [UUUU]

md0 : active raid1 sda1[5] sdc1[3] sdd1[6] sdb1[4]
4190208 blocks super 1.2 [4/4] [UUUU]

unused devices: <none>

/var/log# mdadm --detail /dev/md126
/dev/md126:
Version : 1.2
Creation Time : Fri Nov 1 10:17:34 2019
Raid Level : raid5
Array Size : 11706503424 (11164.19 GiB 11987.46 GB)
Used Dev Size : 3902167808 (3721.40 GiB 3995.82 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent

Update Time : Fri Nov 5 20:15:36 2021
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0

Layout : left-symmetric
Chunk Size : 64K

Consistency Policy : unknown

Name : 0e349ed8:Volume_Backup-0 (local to host 0e349ed8)
UUID : a5655641:0de3a15d:04ae0e91:b294b7d0
Events : 235152

Number Major Minor RaidDevice State
5 8 3 0 active sync /dev/sda3
4 8 19 1 active sync /dev/sdb3
6 8 51 2 active sync /dev/sdd3
3 8 35 3 active sync /dev/sdc3

/dev/md127:
Version : 1.2
Creation Time : Fri Nov 15 09:24:58 2019
Raid Level : raid5
Array Size : 5860115712 (5588.64 GiB 6000.76 GB)
Used Dev Size : 1953371904 (1862.88 GiB 2000.25 GB)
Raid Devices : 4
Total Devices : 3
Persistence : Superblock is persistent

Update Time : Fri Nov 5 20:15:55 2021
State : clean, degraded
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0

Layout : left-symmetric
Chunk Size : 64K

Consistency Policy : unknown

Name : 0e349ed8:Volume_Backup-1 (local to host 0e349ed8)
UUID : 31979138:f23cfef8:dca0bbed:4e1804e3
Events : 113565

Number Major Minor RaidDevice State
- 0 0 0 removed
1 8 36 1 active sync /dev/sdc4
2 8 20 2 active sync /dev/sdb4
3 8 4 3 active sync /dev/sda4

Sandshark
Nov 06, 2021
I agree it doesn't look like it's expanding. First, make sure a 4th partition was created: fdisk -l /dev/sdd. You can also compare the size of the 4th partition to another drive's: fdisk -l /dev/sdc. If the partition is there and the right size, then the following should add it or give you an error message as to why it won't: mdadm /dev/md127 --add /dev/sdd4 --verbose.

If the partition isn't there, don't try to use fdisk to create it, it'll refuse to start it in the right place. I recommend you install and use parted for that.

11 Replies

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StephenB
Guru - Experienced User
Nov 06, 2021
The array is degraded because you replaced a drive. It will remain degraded until the resync completes.

"Degraded" means that there is no RAID redundancy, so if one of the original disks fails the volume will be lost.

XAffi wrote:

2x WD60EFAX;

The WD60EFAX drives use SMR technology. Several folks here have found they misbehave in OS-6 ReadyNAS. SMR drives have variable write speeds (sustained writes can result in glacial speeds).

Generally I don't recommend them for any NAS - not saying you should replace them, but I do suggest keeping an eye out for problems.
- XAffi
  Aspirant
  Nov 06, 2021
  Hi Stephan.
  Thanks for your reply.
  1. "SMR-Drives"--- I have them since almost 2 years now and yes, I am in the progress of replacing them step-by-step - the one I replaced was also an "SMR".
  2. Is resync really running? Usually I see it in the /proc/mdstat. Any proposal where I can see if resync is running if it is not shown on the readynas itself, the web-interface or in the /proc/mdstat file?
  - StephenB
    Guru - Experienced User
    Nov 06, 2021
    XAffi wrote:
    
    2. Is resync really running? Usually I see it in the /proc/mdstat. Any proposal where I can see if resync is running if it is not shown on the readynas itself, the web-interface or in the /proc/mdstat file?
    
    That's a good question. Usually it is shown on the volume page. Your mdstat post shows sdd is missing from md127 (but it is in the md126 raid group).
    
    What drive did you recently replace?