Fatal Trap 18 after Putting bad memory into NAS now I have no ZFS Pools

[DaveG]

I bought some extra ram for my machine which initially stopped machine from booting. I tried it in a different slot and it booted ! Great I thought Ive now got my 8Gb of ram. Then the server crashed. On restart I kept getting an Error. Fatal Trap 18. and it would stop at a prompt db> it would not boot any further and load the GUI.

I disconnected all the drives and it wold then boot. I connected one set of drives and it booted and told me:
cannot import 'Asus4TB': I/O error
Recovery is possible but will result in some data loss.
Returning the pool to its state as of Fri Feb27 13:19:34 2015 should correct the problem. Approximately 44 seconds of Data must be discarded, irreversibly. Recovery can be attempted by executing zpool import Asus4TB -F

It then recomends a scrub of the pool.

I ran the command, and the pool has appeared back in the GUI but it was unable to mount the pool:

cannot mount 'Asus4TB': failed to create mountpoint

The scrub is still running.

Please please can some on help.

 

[Bidule0hm]

You should have added "-R /mnt" to the import command. You should also have searched what this command do and how to use it instead of blindly execute it, now I don't know how you can correct this...

 

[DaveG]

Hey BiduleOhm yes indeed I should have found this forum first! Is there no way of running the import again but including the /mnt


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[Bidule0hm]

You can always export the pool and then re-import it with the correct command but there is maybe a better solution. Wait for an answer from a more knowledgeable member than me ;)

 

[DaveG]

Ok I'll take your advice and ill sleep on it! I'll check back here in the morning. Thanks for your help


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[Bidule0hm]

Ok ;)

You're welcome ;)

 

[jgreco]

Also, there's a nice bit on testing your hardware prior to putting it into production somewhere over in the hardware section. Adding unknown hardware to a production system is fraught with peril - as you've discovered.

People always seem to think I'm joking when I say that hardware actually has to be tested prior to dumping it into production.

 

[DaveG]

Ok. Scrub has finished and I have rebooted the server. And the volume is back!! Woo hoo. Now fingers crossed that my other volume will work too!


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[DaveG]

Having no luck with my other pool of drives. Two 3TB Drives. I get the error in the following image and the system hangs completely or has a db> prompt. Is there anything I can do.

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[cyberjock]

That sure looks like a zpool that is corrupted beyond being mountable. Looks like you should plan to recover from backup or be prepared to pay a pretty penny to get your data back.

 

[DaveG]

There's absolutely nothing to even try to do then? Just reformat the disks then is it. I have about 3/4 backed up and the rest as low res images. So not the absolute end of the world. But how achievable would it be if I can afford to pay, and any ideas of how much?


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[cyberjock]

There's absolutely nothing to even try to do then? Just reformat the disks then is it. I have about 3/4 backed up and the rest as low res images. So not the absolute end of the world. But how achievable would it be if I can afford to pay, and any ideas of how much?

I will tell you right now that you won't pay it. Got $17k+ USD? If not then you can't afford it. ;) The only entity I've seen that did paid recovery with recovery professionals paid $17k USD to get 500GB of data back.

It's one of those things that "if you have to ask you can't afford it".

As for achievable, there is no way to know. In fact, you'll have to pay them just to find out *if* they can recover the data.

There are things you *can* try to do besides just "reformatting the disks", but the flowchart for that is like 100 steps long and not something I'm going to try to get involved in through a forum. Its just not worth my effort as a volunteer. Sorry. It would be like you asking how to build a vehicle from scratch just by buying parts from a nearby dealership. Totally doable, but not something you can try to explain in a reasonable period of time.

 

[DaveG]

Ok shall we start with the car and if that works give the data recovery a go ! oh bugger


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[jgreco]

By the way, the "volume is back" is great but the only thing you should do with it at this point is to copy the data off, blow it away, and reload the data.

The problem with ZFS is that it is an insanely complicated on-disk format, and a large part of it is that it assumes that the error detection and recovery is going to catch corruptions and problems. ZFS has very little ability to deal with a scrambled pool, so if bull**** gets written out to the pool with a valid checksum, such as when something goes bad in main memory and then gets written, your pool suffers.

One thing you might be able to try is to see if you can find another ZFS implementation that is capable of accessing the pool. The best way to do that is to make a clone of the existing pool drives and then to experimentally see if any of the other cutting-edge ZFS releases have better luck mounting it.

 

[DaveG]

excuse my ignorance but What might another zfs implementation be??


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[TinTIn]

Open Indiana, Oracle Solaris, Omni OS, the list goes on but they are the main contenders.


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[TinTIn]

Install Napp-it for a nice web GUI like FreeNAS.


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[HoneyBadger]

Install Napp-it for a nice web GUI like FreeNAS.

A web GUI, yes ... a nice one? I'll bite my tongue. ;)

I'd use the OmniOS LiveCD and try to import the pool with the readonly=on flag.

 

[TinTIn]

Agreed. The FreeNAS GUI is MUCH better and the terminology makes more sense if you understand ZFS.


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[TinTIn]

Omni OS can be a bit funny about hardware in my experience so if you have trouble try one of the others.


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