Recovering from failed HDD…

[Dave.B]

I thought I would ask here as the NSLU2-Linux Wiki doesn’t seem like a friendly place to ask:

I’ve just received my external HDD back from the manufacturers after it failed a week ago. Luckily they repaired it (under warranty) instead of replacing it so I just plugged it back in, started the slug and everything went back to normal. But I have little confidence in this disk now (especially as I can’t set it to spin down), so I know this is going to happen again.

However, it got me thinking – how would I have recovered fom this if they had sent me a new disk? The music isn’t a problem as it’s backed up on DVDs, but I’m thinking about unslinging an already unslung slug to a new disk.
Has anyone done this? Is it difficult? I’ve searched and only found snippets of high-level Linux techno jargon. Surely somebody must have had to re-unsling?

Any help or advice (for me or for anyone searching) will be appreciated.
Thanks

[rpedde]

@Dave.B wrote:

I thought I would ask here as the NSLU2-Linux Wiki doesn’t seem like a friendly place to ask:

I’ve just received my external HDD back from the manufacturers after it failed a week ago. Luckily they repaired it (under warranty) instead of replacing it so I just plugged it back in, started the slug and everything went back to normal. But I have little confidence in this disk now (especially as I can’t set it to spin down), so I know this is going to happen again.

However, it got me thinking – how would I have recovered fom this if they had sent me a new disk? The music isn’t a problem as it’s backed up on DVDs, but I’m thinking about unslinging an already unslung slug to a new disk.
Has anyone done this? Is it difficult? I’ve searched and only found snippets of high-level Linux techno jargon. Surely somebody must have had to re-unsling?

Any help or advice (for me or for anyone searching) will be appreciated.
Thanks

unslung is set up to work as “slung” if the unslung drive isn’t plugged in. In that case, I believe that when you plug in a blank drive, you’ll be basically at the position you were at when you had upgraded the firmware but haven’t done the unslinging.

It should be simply a matter of partitioning and formatting the drive through the web interface and then unslinging as per the unslung README.

That’s the theory anyway. 🙂 Haven’t tried it in practice.

— Ron

[g0pkh]

It is possible to unsling again without reflashing the slug.

I have done it on an unslung5.5 version.
You have to remove 2 files from the flash memory however.

Here is the relevant info from the Wiki.

telnet in and remove the “/.unslung” and “/.sd??root” files on the internal flash (/.sd?? being sda1 etc depending on the usb port your drive was connected to) reboot once again
telnet in again, attach the external flash drive, and “unsling” it again.

Failing to remove the files results in the SLUG appearing to unsling, but it will never boot, guess how I found out.

Not quite sure of this process on 6.8 beta though.

I know what you mean about the wiki not being the friendliest place to ask questions. 🙁

Hope this helps

You might consider as a backup in the future, the possibility off adding a second harddrive and doing a disk to disk backup (fix it first, see the wiki) between the 2 drives. You can then just switch the drives over in the event of a failure.

[Dave.B]

Thanks Ron and g0pkh. So it doesn’t look too hard then.

@ g0pkh: I did find that little bit of info about deleting those files, but I must confess, even after reading it several times, I can’t quite figure out what it means. When boredom next strikes, I’ll telnet in and see if I can find wherwe they are.

Cheers
Dave

[Dave.B]

Well, almost exactly three years later and here I am in the exact situation I enquired about above. I think I’ve got the solution thanks to g0pkh’s reply above, but just to be sure…

I would do:

rm .unslung

rm .sda1root

Then with a new formatted drive (more likely a flash drive) plugged into USB port 1, I would do:

unsling disk1

That should be me up and running again, right?
Anyone see anything wrong with that?

[Dave.B]

And here I was, waiting for a serious reply 👿

Still haven’t got it working. Apart from missing the sbin/ from the unlsing command… it apears to unsling correctly but the slug refuses to boot from the disk.

[g0pkh]

Hi Dave.

So sorry I missed your reply.

Have you got this working again yet, can you see the two files on the slug ?

Telnet in and cd /
then ls -a this should confirm the existance of the files.

rm /.unslung
then
rm /.sd?root

ls -a again they should be gone.

Attach the drive, format it and try the unsling again.

Its a long time since I used my slugs however as I only use Buffalo LSII’s now.

Pete

[Dave.B]

Thanks Pete,
Please don’t take my previous post the wrong way… there was a spam post between that has since been removed.
I have removed the two files and confirmed that they are gone, and unslinging appears to work, but on rebooting the slug, everything seems “a bit weird”… I log in as root using the password on the disk, not the internal flash, but I can’t use IPKG, it gives “No such file or directory”. I Googled and found another command (something like CIPKG) that appeared to work when I CIPKG Update, but I have a nasty feeling that the slug isn’t booting off the disk and all I”ve done is fill up the internal flash.

I don’t want to format the disk as it was the backup of the disk that failed. I think the plan now is just to reflash the slug, maybe with 6.8, and unsling to a USB flash drive.

I’d be interested in your thoughts on this though.
Thanks for the reply.
Regards
Dave

[g0pkh]

Hi Dave.

It does sound as that may the case.
That is strange though because I have reslung both of my slugs many times in the past.
The last time I used then was with a pair of 2.5″ laptop drives fitted in cheap usb powered enclosures.

I am not using my slugs anymore now since I rely on the LSII’s, so I cant really comment much further.
I assume you have been using V5.5. I always found that the best version.

I think personally you would be better off reformatting that drive, and starting from scratch
Why not connect the drive to a PC and use a EXT3 file system driver to backup your data first ?
Or get yourself another drive they are really cheap now.

I have never tried unslinging to a flash drive so cant really comment. I didnt really like the idea of all the fiddling about
preventing unnecessary writes to the flash etc.

The slug also has a reset to factory defaults option in the menu too, I have had to use that on occasion.

Best of luck.

Pete

[Dave.B]

Thanks for the advice Pete,
Unfortunately I’ve had another HDD failure in my main PC so the priority is getting that up an running again first.
I think you are correct… a brand new disk is probably in order, then reflash and unsling to that.
I am quite tempted by a Linkstation though, now you mention it!

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