Arch Linux

newsboost

Member

Registered: 2016-07-24

Posts: 157

Can't read Synology NAS HD in Arch Linux - works in Ubuntu: mdadm -Asf

Hi all,

I've always been very happy with Arch Linux and until now I think I haven't seen any situations where there were something that could be done in Ubuntu, but couldn't be done in Arch Linux. I have a problem with "core/mdadm 4.1-2 - A tool for managing/monitoring Linux md device arrays, also known as Software RAID", it simply doesn't work on Arch Linux as it does on Ubuntu... In Ubuntu things are *really* simple, I just do [1]:

apt-get install -y mdadm lvm2
mdadm -Asf && vgchange -ay
mount /dev/md3 /mnt/extHD

It's a simply as that, in Ubuntu (from a live DVD/USB)! In Arch Linux, I try to do the same but I get:

# mdadm -Asf && echo 'yes'
mdadm: No arrays found in config file or automatically
# vgchange -ay
  1 logical volume(s) in volume group "Windows_KVM" now active

But please don't get confused - that "Windows_KVM" isn't the right volume group, from the harddisk I'm trying to read (it's from an existing SSD). A bit more info here:

# mdadm --assemble --scan -v
mdadm: looking for devices for further assembly
mdadm: no recogniseable superblock on /dev/md/Syn:3      <---- THIS IS THE ONE I WANT TO ACCESS/READ!
mdadm: no recogniseable superblock on /dev/dm-2
mdadm: no recogniseable superblock on /dev/dm-1
mdadm: no recogniseable superblock on /dev/dm-0
mdadm: /dev/sdc3 is busy - skipping      <---- THIS IS THE ONE I WANT TO ACCESS/READ (corresponds to /dev/md127!)
mdadm: no recogniseable superblock on /dev/sdc2
mdadm: no recogniseable superblock on /dev/sdc1
mdadm: Cannot assemble mbr metadata on /dev/sdc
mdadm: no recogniseable superblock on /dev/sdb2
mdadm: no recogniseable superblock on /dev/sdb1
mdadm: Cannot assemble mbr metadata on /dev/sdb
mdadm: no recogniseable superblock on /dev/sda6
mdadm: no recogniseable superblock on /dev/sda5
mdadm: no recogniseable superblock on /dev/sda3
mdadm: Cannot assemble mbr metadata on /dev/sda2
mdadm: Cannot assemble mbr metadata on /dev/sda1
mdadm: Cannot assemble mbr metadata on /dev/sda
mdadm: No arrays found in config file or automatically

The conclusion is: For some reason the command "mdadm -Asf" just don't work straight out of the box, as in Ubuntu - could anyone please help and tell what I'm doing wrong? I've tried many things, but the conclusion is that I don't understand enough of RAID to fix this myself... I'm grateful for any help/feedback/suggestion, that can fix this - as I prefer Arch over Ubuntu! :-)

[1] https://www.synology.com/da-dk/knowledg … using_a_PC

newsboost

Member

Registered: 2016-07-24

Posts: 157

Re: Can't read Synology NAS HD in Arch Linux - works in Ubuntu: mdadm -Asf

Damn... Sorry... Seems this made things I've been struggling with for such long time work:

# mdadm --detail --scan >> /etc/mdadm.conf 
# mount /dev/md127 /mnt/extHD

# cat /proc/mdstat 
Personalities : [raid1] 
md127 : active raid1 sdc3[0]
      7809204544 blocks super 1.2 [1/1] [U]
      
unused devices: <none>

But could anyone please explain a RAID noob as myself, why I have to do this in Arch Linux but not in Ubuntu? It's a harddisk that won't permanently be in this computer, so I prefer not to mess with .conf-files for things like this... As I consider trying to use 2 harddisk's for software RAID in the future (have only experience with LVM and adding physical partitions), I would appreciate a few hints/comments, before I mark this a solved and consider the case closed.... Thanks for any help, you may have!