btrfs partition missing

[Adolpha_arts]

Good day everyone 

So this morning I was working on getting something set up on my new pc and I went to get the file off my unraid server and found one of my drives missing. I went and looked at the server interface  and saw the that drive was listed as “Unmountable: no file system” and was asking to formate that drive. So I thought thats was odd the SMART report looked fine. So i took the server offline and pulled the Unraid boot disk and booted in to an ssd with Ubuntu on and it showed the same with the main Disks tool that Ubuntu comes with. Then I tried Gparted tool and did show something was wrong with the drive.

The first thing was this error “end of file while reading /dev/sdc”  The button I pressed was “Ignore” to move on. Then got this error “The primary GPT table is corrupt, but the backup appears OK, so that will be used.”  The button I pressed “ok”. 

 after doing some quick Googling I decided to right click on the partition and use the “New UUID” option to see if that would work. It failed!

I think the drive is fine with the data is still there. I just need to figure out how to fix the partition table. 

gparted_details.htm

[trurl]

Was this a disk in the parity array, was it part of a cache pool, was it the only cache drive, or was it unassigned?

 

You should have asked for help before trying to work with the disk outside of Unraid. If the disk was part of the parity array then you have probably invalidated parity. All repairs should first be attempted within Unraid.

 

 

[Adolpha_arts]

the drive is a cache drive 3tb about 20% 50% full last time i looked. all the disk on that list are normally in the server but the ssd is pasthough to a VM. there is no partity disk at this time it is dead and needs replaced.

i know my server is in need of some TLC or just an over hall, just not had the money to do it. i just trying to keep it up and run right now. any help in fixing the drive would be great.

[JorgeB]

Was the cache a pool? Please post the Unraid diagnostics: Tools -Z Diagnostics

[Adolpha_arts]

here you go i didnt what "-Z" is for but i got the Diagnostic zip as a whole and it not a pool. 

wolfden-diagnostics-20200917-1335.zip

[JorgeB]

7 minutes ago, Adolpha_arts said:

didnt what "-Z" is for

Sorry, that was a typo, tools -> diagnostics is what I meant to write.

 

Try this:

 

-stop array

-change cache slots to 1

-click on cache and set filesystem to "auto"

-start array and post new diags

 

 

[Adolpha_arts]

ok i moved it to cache 2 slot it was in slot 1, but as soon as i did it gave a warning "udma crc error count is 3" this is new and did not show that this morning. also i don't know where you met to change that setting that field is unchangeable.

[JorgeB]

Don't move to slot 2, leave the ssd on the 1st slot and change total cache slots to 1.

[Adolpha_arts]

ok did the changes and started the array but looks to be the same as before “Unmountable: no file system”. the new diagnostics zip is below.

 

wolfden-diagnostics-20200917-1409.zip

[JorgeB]

There's a problem with the partition, unassign cache, start the array, install the Unassigned Devices plugin and see if there's an option to mount the disk there.

[Adolpha_arts]

so i installed the plugin and unassigned cache drive but now the array does not start. i see nothing that the plugin help with. and i knew that there was something was wrong with the partition. please read my first post. Gparted tool did see the issue was the partition table is missing but the backup table is there. how do we get the back up table to work or fix the first partition table.

[JorgeB]

1 hour ago, Adolpha_arts said:

but now the array does not start

There's a checkbox to allow starting the array without the cache assigned.

 

1 hour ago, Adolpha_arts said:

i knew that there was something was wrong with the partition

According to UD there's no partition, post the output of:

 

fdisk -l /dev/sde

 

 

 

[Adolpha_arts]

ok here you go. it say the same thing?

[JorgeB]

It appears that the GPT corruption is causing an error that makes Unraid not even detect the exiting partition, I have no experience repairing GPT partitions, quick google search found this:

 

http://www.rodsbooks.com/gdisk/repairing.html

 

Another option would be to create a new partition on top of that one, it should work but I would recommend cloning the disk first with dd and try on the clone, if it works it might only mount with UD, not on the array/cache, but it would at least allow you to access the data.

 

P.S. don't try to change the btrfs UUID, it won't help and can cause further problems.

[JorgeB]

I had some time to take a look at this, if you still need help to repair the corrupt GPT partition post back, it's easily done with gdisk.