segfault after removing HDD

[Dave-Kay]

Dear all,
i tried to remove a HDD with this 
https://wiki.unraid.net/Shrink_array
it all went well, until i stopped the array. it got stuck in unmounting drive 7 which i removed with this method, saying unmount drive 7, drive not mounted.
i read in the forum, the only way out of this loop seems to be rebotting the server.
After the reboot i followed the manual again and made a new config and started the array.
it got stucked in mounting the disks, as it said and told me this

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May  1 17:57:16 UNRAID emhttpd: shcmd (205): rmdir /mnt/disk1
May  1 17:57:16 UNRAID emhttpd: mounting /mnt/cache
May  1 17:57:16 UNRAID emhttpd: shcmd (206): mkdir -p /mnt/cache
May  1 17:57:16 UNRAID emhttpd: /sbin/btrfs filesystem show /dev/sdc1 2>&1
May  1 17:57:16 UNRAID emhttpd: Label: none  uuid: b843e3cb-a537-434b-9212-747a404af834
May  1 17:57:16 UNRAID emhttpd:  Total devices 2 FS bytes used 4.10GiB
May  1 17:57:16 UNRAID emhttpd:  devid    1 size 223.57GiB used 17.03GiB path /dev/sdc1
May  1 17:57:16 UNRAID emhttpd:  devid    2 size 223.57GiB used 17.03GiB path /dev/sdk1
May  1 17:57:16 UNRAID kernel: emhttpd[6330]: segfault at 10f ip 0000151709d96236 sp 00001517092800c8 error 4 in libc-2.37.so[151709d0a000+169000] likely on CPU 3 (core 3, socket 0)
May  1 17:57:16 UNRAID kernel: Code: 00 00 66 90 66 0f ef c0 66 0f ef c9 66 0f ef d2 66 0f ef db 48 89 f8 48 89 f9 48 81 e1 ff 0f 00 00 48 81 f9 cf 0f 00 00 77 6a <f3> 0f 6f 20 66 0f 74 e0 66 0f d7 d4 85 d2 74 04 0f bc c2 c3 48 83
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can anyone tell me, what to try?
 

[JorgeB]

Can tell you why but you will need to reboot to make it usable again.

[JorgeB]

If it happens again after a reboot post the diagnostics.

[Dave-Kay]

yes it does.
i allredy tried several reboots
here

unraid-diagnostics-20230501-1829.zip

[JorgeB]

Don't start the array, click on cache, change the fs from auto to btrfs and choose the correct profile you are using, then start the array to see if that helps.

[Dave-Kay]

wow! Thank you!
I was suspecting the cache-Drives, but i didn't know how to prove it.
Where did you find the problem.
And well, THANK YOU!

[JorgeB]

I've seen this before, though not quite sure why it happens on very rare occasions. 

[Dave-Kay]

While the cache isn't encrypted, could it be possible the encryption of the array has a play in it?

[JorgeB]

Nope, the other server I see this has no encryption for anything, it happens every time you try to import an existing btrfs pool, like after a new config, if the pool fs is set to auto it segfaults, but I can only reproduce this with one server, and it has nothing in common that I can see with yours, so kind of a weird issue.

[JorgeB]

One thing that might help, if you can, stop the array and post the output of

btrfs fi show

 

[Dave-Kay]

Label: none  uuid: b843e3cb-a537-434b-9212-747a404af834
        Total devices 2 FS bytes used 4.12GiB
        devid    1 size 223.57GiB used 17.03GiB path /dev/sdb1
        devid    2 size 223.57GiB used 17.03GiB path /dev/sdj1