[SOLVED] Nextcloud - RPi 4- mdadm unable to remove raid 5 array

g4njawizard · 12-09-2020, 05:12 AM

Hi everyone,

I am currently trying to create a new raid 5 array, because I experienced huge performance issues when running updates on nextcloud. It takes almost a complete day to create a backup, download files, extracting and replacing files.
I already used nextcloudpi and the normal server nextcloud version on my raspberry. Both lack in terms of reading and writing on the disks. But when I upload and download files from the cloud it's running smooth.

On my Raspberry Pi 4 4GB, I have 4 SATA Disks with each 2TB. First time I created an array, I used Raid 5 with a spare disk. But this conestellation persists every time, even when I delete every information. I want this time to use all 4 Disks without a spare part.

I already zero'd all 4 Disks. It took almost ~6-8 hours for each disk.
But the write speed was IMO ok. I had a write speed on each disk from round about 130-140Mb/s.

What I've also tried:

Code:

OK root@ncloud:~# mdadm --stop /dev/md127 
mdadm: stopped /dev/md127    
OK root@ncloud:~# mdadm --remove /dev/md127
mdadm: error opening /dev/md127: No such file or directory
Error root@ncloud:~# cat /proc/mdstat 
Personalities : [raid6] [raid5] [raid4] 
unused devices: <none>
OK root@ncloud:~# mdadm --examine --brief --scan  --config=partitions
ARRAY /dev/md/vol1  metadata=1.2 UUID=46c6092a:69f8d8f4:23bfc213:a9fb2222 name=ncloud:vol1
OK root@ncloud:~# mdadm --zero-superblock /dev/sda /dev/sdb /dev/sdc /dev/sdd
OK root@ncloud:~# wipefs -af /dev/sda /dev/sdb /dev/sdc /dev/sdd
OK root@ncloud:~# mdadm --examine --brief --scan  --config=partitions

But still the same Array with spare disk is keep coming back.

Code:

root@ncloud:~# mdadm --create --verbose --chunk=128 /dev/md/vol1 --level=5 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: size set to 1953382400K
mdadm: automatically enabling write-intent bitmap on large array
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md/vol1 started.
OK root@ncloud:~# mdadm --detail /dev/md/vol1
/dev/md/vol1:
           Version : 1.2
     Creation Time : Wed Dec  9 08:09:29 2020
        Raid Level : raid5
        Array Size : 5860147200 (5588.67 GiB 6000.79 GB)
     Used Dev Size : 1953382400 (1862.89 GiB 2000.26 GB)
      Raid Devices : 4
     Total Devices : 4
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Wed Dec  9 08:09:30 2020
             State : clean, degraded, recovering 
    Active Devices : 3
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 1

            Layout : left-symmetric
        Chunk Size : 128K

Consistency Policy : bitmap

    Rebuild Status : 0% complete

              Name : ncloud:vol1  (local to host ncloud)
              UUID : 46c6092a:69f8d8f4:23bfc213:a9fb2222
            Events : 2

    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
       4       8       48        3      spare rebuilding   /dev/sdd

michaelk · 12-09-2020, 08:21 AM

This appears to be normal and can be overridden with the --force option.

Have you waited until the array was fully rebuilt to see if the 4th drive became active?

https://marc.info/?l=linux-raid&m=112044009718483&w=2

g4njawizard · 12-09-2020, 09:52 AM

Thanks for the reply. I am waiting now for some hours. Yet it's at 45%. I hope Disk 4 becomes active and not spare then. I will answer if it didn't.

edit: rebuild has finished. it works now!