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Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

WallyZ21
Aspirant

Access ReadyNAS RNDU2000 mirrored drive directly from Linux.

Also posted in Ubuntu Forum (http://ubuntuforums.org/showthread.php?t=2272848)
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Drive is one from a mirrored pair out of a ReadyNAS RNDU2000 (2 drive unit). I assume this drive uses 16K file system block size.

I have it attached via a USB<->SATA adapter. (tableau write blocker)

Fdisk sees the device as /dev/sdb1 (GPT)

# file -sL /dev/sdb1
/dev/sdb1:Linux Software Raid version 1.2 (1) UUID=d0...b0 name=A0...3A:0 level=1 disks=2

Attempted to reassemble from one drive (force assemble with only one member with --run):

# mdadm --assemble --run /dev/md0 /dev/sdb1
mdadm: cannot re-read metadata from /dev/sdb1 - aborting

Attempted normal mount:

# mount -o ro /dev/sdb1 /mnt/drive
mount: unknown filesystem type 'linux_raid_member'

Attempted to fuse mount drive:

# mkdir /mnt/drive
# fuseext2 -o ro,allow_other /dev/sdb1 /mnt/drive
... Probe failed [main (fuse-ext2.c:347)]

Tried to scan for volume groups:

# vgscan
...
No volume groups found

I'm using Ubuntu 14.04LTS
fuse-ext2 version '0.4', fuse_version:'29'
-------------------------------------------------------------
I have also tried the Ubuntu9.10 VMware image referred to in these forums (http://www.readynas.com/forum/viewtopic.php?f=11&t=35153&start=105#p275675)
without any success.

The drive (both drives) is working in the ReadyNAS unit but that is not my issue!

Any ideas how I can mount and access this drive from Linux?
Message 1 of 11
mdgm-ntgr
NETGEAR Employee Retired

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

The RNDU2000 is the Ultra 2, for which the procedure to attempt to recover data using Linux is different to that used for Sparc ReadyNAS.

For the Ultra 2 you could do e.g.

# mdadm --assemble --scan
# vgscan
# vgchange -a y
# mount -o ro /dev/c/c/ /mnt/drive

Note the steps above do not include checking disk health, the RAID superblock etc. which would be advisable if you don't know what state the array is in.
Message 2 of 11
WallyZ21
Aspirant

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

Thanks for the reply:

#mdadm --assemble --scan
mdadm: cannot re-read metadata from /dev/sdb3 - aborting
mdadm: cannot re-read metadata from /dev/sdb2 - aborting
mdadm: cannot re-read metadata from /dev/sdb1 - aborting
mdadm: No arrays found in config file or automatically

I tried this on both drives!

I must mention at this point the drive is write blocked (read only).
Message 3 of 11
mdgm-ntgr
NETGEAR Employee Retired

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

Well the array is clearly not in a good state then.

I assume you have no backup?

Have you checked the health of the disks?

There must be a reason the disks have gone read-only.
Message 4 of 11
WallyZ21
Aspirant

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

No the contrary, the array is in a perfect state. This is an exercise to access a perfectly working array from Linux.

Once I figure the correct commands for a known working array I will move onto faulty arrays.
Message 5 of 11
mdgm-ntgr
NETGEAR Employee Retired

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

Perhaps try a different adapter to connect the disk to your PC?
Message 6 of 11
WallyZ21
Aspirant

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

mdgm wrote:
Well the array is clearly not in a good state then.

I assume you have no backup?

Have you checked the health of the disks?

There must be a reason the disks have gone read-only.


I apologize and you may after all be right. I wasn't paying close enough attention to the output of file -sL and I have found something weird in the setup.

There are 3 partitions on each disk.

file -sL reports /dev/sdb1 is level=1 disks=2
file -sL reports /dev/sdb2 is level=1 disks=2
file -sL reports /dev/sdb3 is level=5 disks=2

Level 5? I didn't think the ULTRA 2000 (2 disk unit) supported level 5.

I must have broken it somehow which is unlikely as I tested the USB<->SATA write blocker.

So to find out if it is actually still working I am going to plug the drives back into the NAS unit and fire it up!!!
Message 7 of 11
WallyZ21
Aspirant

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

Plug the drives back into the ULTRA 2 and it starts up fine and I can access all the shares.

Back to square one!!!

So how can I access these drives (with the weird RAID 5 setup) from Linux?
Message 8 of 11
mdgm-ntgr
NETGEAR Employee Retired

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

It uses that "weird RAID 5 setup" to enable expansion from 2 disks to 3 in systems that support that.

It sounds like you should try a different USB to SATA adapter or better yet connect the disks to internal SATA ports and boot off a Linux Live CD
Message 9 of 11
StephenB
Guru

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

Many older USB2 adapters don't support drives > 2 TB.
Message 10 of 11
WallyZ21
Aspirant

Re: Access ReadyNAS RNDU2000 mirrored drive directly from Li

StephenB wrote:
Many older USB2 adapters don't support drives > 2 TB.


Some don't!

But this one has been tested (by me) up to 4TB.

And the two drives in question are only 1.5TB anyway!!!
Message 11 of 11
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