Waiting for lock during backup

[miednr]

I am waiting for my backups to continue for some couple of hours now. They keep stuck on 39% each.

The info in cloudron is: "waiting for lock" and in the logs hundreds of lines like this one appear:

2026-02-07T17:39:03.085Z box:locks Attempt 159 failed. Will retry: Locked by 652

CPU 5%, RAM 33%, Disk I/O and Network I/O are low.

cloudron-support --troubleshoot is all OK.

What could be the reason? I tried searching the docs and the forum. I would understand the message "wait for unlock", but what kind of lock does cloudron mean?

BTW: I am using different targets, of course...

[james]

Hello @miednr
Can you please provide the full log file from that failing backup?
What Cloudron version are you currently using?

[miednr]

Thanks @james

Cloudron Version is 9.0.17 and the logs do have repeated entries like that:

Feb 07 20:30:16 box:locks Attempt 824 failed. Will retry: Locked by 652
Feb 07 20:30:26 box:locks Attempt 1 failed. Will retry: Locked by 652
Feb 07 20:30:26 box:locks Attempt 825 failed. Will retry: Locked by 652
Feb 07 20:30:36 box:locks Attempt 1 failed. Will retry: Locked by 652
Feb 07 20:30:36 box:locks Attempt 826 failed. Will retry: Locked by 652

Last lines before that are:
2026-02-07T17:12:37.003Z box:backuptask copy: copied backupinfo successfully to 2026-02-07-171219-870/app_xyz.domain.com_v1.0.1.backupinfo
2026-02-07T17:12:37.007Z box:backuptask fullBackup: app xyz.domain.com backup finished. Took 1.105 seconds
2026-02-07T17:12:37.011Z box:locks write: current locks: {"full_backup_task_XYZ":null,"app_backup_XYZ":"652","full_backup_task_XYZ":null}
2026-02-07T17:12:37.011Z box:locks release: app_backup_XYZ
2026-02-07T17:12:37.011Z box:tasks updating task 653 with: {"percent":39.095238095238095,"message":"Backing up domain.com (8/18). Waiting for lock"}

First I thought this was related to my storage, but it also happens with the local backup (SSD).

[james]

Hello @miednr
It looks like the app at domain.com is failing to get locked.
What app is installed under that domain?

[miednr]

That is a WordPress (Dev).

[miednr]

I got an idea, but I am not sure...:

I have three backups of the whole system at the same time. Two are stuck on WordPress and the third is very slow progressing on the same WordPress. I guess, the "lock" means, that the other two backups wait for the third process to "unlock" their "lock" on that App. Is this true? I start to understand. But, why is this the default behavior?

[james]

Hello @miednr

@miednr said in Waiting for lock during backup:

I have three backups of the whole system at the same time.

Sorry that I have to ask again for clarification.
Are three full backup processes running at the same time?
Do you have three backup sites?
Normally only one backup process should run at a time.

Yes, the backup process locks apps for a backup and unlock them after it finished with the app.

Maybe it is a good idea to reboot the system once and try one full system backup again.

[miednr]

Yes, I have three backup destinations. But, I see und understand that's not a good idea to do multiple backups at a time... My server is not on limits (CPU 5%, RAM 33%, Disk I/O and Network I/O are low). I think, it will run through, but it's slower than doing the backups one at a time. But the reason seems to be the "lock" of Apps by Cloudron Backup. Will not repeat that... But for now, I will let the system find it's way during the night.

[joseph]

Yes, you have to adjust the schedule manually to not overlap. Otherwise, if a single app is backing up to multiple sites in parallel, they will get serialized internally (with the lock).