BTRFS error when running Duplicati backup

[ohj]

I've set up Duplicati to do a backup of my data and container backup shares every night at 03:00.  Before that I create a local backup of all my containers' appdata folders at 02:00, and deposit the bacup in the forementioned backup share.  This has worked fine for a while, but I noticed now that the backup hasn't run successfully for some weeks.  And today I noticed that I get a BTRFS error in my unRAID system log when trying to run a Duplicati backup process.  In Duplicati I just get an IO disk error without any more information.

 

Any idea what can be the problem here?  As far as I can tell I'm not trying to backup a folder that doesn't exist anymore or anything like that.  Why would unRAID complain about Duplicati reading the data and backup shares?

 

 

[JorgeB]

There's corruption in the tree block, best bet is to backup and re-format.

[ohj]

What do you mean?  Back up all the data on all the shares in the disk array, and then reformat the array??  That's a huge task.  How did this happen, and is this something I can expect to happen often?  The drives are only two or three months old.

 

Also, I'd like some more confirmation before doing something like this.  I have 8-10 containers running on my system with their respective appdata folders, and I have a data share used on several computers at home.  I haven't noticed any problems or error messages related to disk IO other than with Duplicati.

Edited March 10, 2021 by ohj

[JorgeB]

20 minutes ago, ohj said:

Back up all the data on all the shares in the disk array

No, backup and reformat sdb, which I assume is your cache but can't say since you didn't post the diagnostics.

[ohj]

Ugh, yeah, I should have noticed the 'sdb' reference.  I apologize - I am still a fairly new unRAID user.  'sdb' is as you say the cache drive, which is a 128GB SSD I earlier used as a boot drive in the server.  I have some shares that store to the cache drive, as you can see.

 

 

I'm also attaching the diagnostics files:  unraid-diagnostics-20210310-1115.zip

 

How would you go about backing up the SSD before formatting it?

[JorgeB]

This is one way:

https://forums.unraid.net/topic/93846-btrfs-error-with-new-system-m2-ssd/?tab=comments#comment-867992

 

[ohj]

Perfect!  I'll give it a try.

On a sidenote, what could have caused this problem?  And why is only starting the backup process in Duplicati triggering the error message?  I'm just wondering if I ought to not use Duplicati because it's causing problems for unRAID or something.

[JorgeB]

Filesystem corruption is most usually caused by an unclean shutdown or hardware problem, like bad RAM.

[ohj]

I've had some unclean shutdowns due to hangs caused by hardware problems (the mainboard USB controller's crapping out on me).  So likely this can be the cause then.

 

But I read that BTRFS corruption is a well-known problem.  So I've changed the file system on the cache drive to XFS, and am currently rebuilding the Duplicati database.  All is well again, at least so far. 🙂

 

Thank you for your help!