btfrs_root_node 38

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sebastianci wrote:

Can you help with further steps for btrfs recovery?

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I haven't needed to do it myself, so it's not something I can give much guidance on.

I can say that you should start in tech support mode with 

# rnutil chroot

That will both start RAID and chroot.

If for some reason, you only want to start RAID, then with OS-6 you'd enter

# start_raids

(not start_raid)

If you have ever expanded your RAID array vertically, you probably will need to enter

# btrfs device scan

This shouldn't hurt if you don't need it.

If you want to try to mount the volume, the normal command is

# mount /dev/md127 /data

But most BTRFS repair tools can't be run on a mounted volume.

You should read up on btrfs check --repair and maybe also btrfs restore

Great thanks

It is good starting point i will do some reading, just to make my work easier: how to gracefully shutdown NAS in tech support mode, shall I run something to stop RAID, I guess I just exit from chroot. How to shutdown NAS then, shutdown command does not work?

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sebastianci wrote:

How to shutdown NAS then, shutdown command does not work?

 

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# shutdown now

should work.  Are you sayng it doesn't?

Yes

# shutdown now
-sh: shutdown: not found

Try rn_shutdown.  That's an r & n (for ReadyNAS), not an m before the underscore.   That's the command for standard SSH, I have never tried it in tech support mode.  It's located in /usr/bin.

Hi sorry for delay. To minimise interactions with my NAS , I was waiting for new HDD.

Now I started and not sure why my nas is md126, see attached screenshot.

Unfortunatelly btrfs commands do not work on md127, md126 checksum incorrect.

Can you say if md126 is an sensible raid alias or i need to rearange something?

Sebastian

also,  rn_shutdown is also not present ?

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sebastianci wrote:

Now I started and not sure why my nas is md126, see attached screenshot.

Unfortunatelly btrfs commands do not work on md127, md126 checksum incorrect.

Can you say if md126 is an sensible raid alias or i need to rearange something?

 

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Your NAS was vertically expanded (disks 1 and 3 appear to be larger), so you have two RAID groups.  Normally md127 would be the original group.  But in your case that appears to be md126.

Have you given up on Netgear tech support?  They should have gotten back to you by now.

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sebastianci wrote:

rn_shutdown is also not present 

 

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You appear to be missing several commands that you ought to have.  shutdown should be in /sbin; rn_shutdown should be in /usr/bin

Did you start with

# rnutil chroot

Or did you skip that?

Thanks for answer,

On the subject of btrfs, thanks: md126 it is.

Mounting as ro does not work : btrfs_root_node+38

Running check --repair:

root@3EPB43EE0025E:/# btrfs check --repair /dev/md126
enabling repair mode
checksum verify failed on 9150299111424 found 10BC57A5 wanted 18B79090
checksum verify failed on 9150299111424 found 10BC57A5 wanted 18B79090
parent transid verify failed on 9150299111424 wanted 88714 found 86890
checksum verify failed on 9150299111424 found 10BC57A5 wanted 18B79090
Csum didn't match
ERROR: cannot open file system

I know you not an expert on btrfs, though any suggestion might put me in right direction.

On netgear tech support

They contacted me origianly, spent 45 minutes on the NAS and decided I need to pay ~£160/hour for data recovery - of course no guarantee.

I am afraid they either want more hours, or recover partial data which does not contain what I have really lost. I accept I will loose 2 weeks of family pictures, so be it.

On shutdown

In chroot I can see both files

/sbin/shutdown

/usr/bin/rn_shutdown

issuing rn_shutdown: causes some noise from disks and nothing happends,

issuing shutdown: "Running in chroot, ignoring request"

After typing "exit",  rn_shutdown, shutdown are no longer present.

If I run new telent also rn_shutdown, shutdown are not present unless I enter chroot

Thanks