Mailcow backup

TCAtCTS

I am new to Mailcow. My first attempt at running the backup script fails. At the start of the script, I see:
Found project name mailcowdockerized
The first sign of errors is this:
/bin/tar: /backup/backup_vmail.tar.gz: Cannot write: Broken pipe
/bin/tar: Child returned status 2
/bin/tar: Error is not recoverable: exiting now

I have mounted a Windows file share for backup. I connected with administrator permissions. I am running backup as root.

In the backup location, I see only mailcow.conf and .x86_64

It appears the problem has something to do with writing to the windows share. I can make a temporary copy of the backup at /tmp/backup and then cp -r the whole thing to the windows share with no problem.
The mount point shows 755 permissions.

DocFraggle

TCAtCTS I am running backup as root

That’s true, but the actual backup is run inside the container, see

mailcow/mailcow-dockerizedblob/master/helper-scripts/backup_and_restore.sh#L110-L113

So your Windows share is mounted inside the container, and then the tar command is run. This could lead to problems I guess.

You could try these mount options for your cifs share and have a look if this works better:

nounix,noperm,cache=none

If nothing works, maybe use a script for your backup: backup to your /tmp directory and move the files to the share after it finished

TCAtCTS

DocFraggle

Thank you for the feedback. It works to backup to a local directory, such as /tmp/backup. I can thereafter move that to my windows share. However, I would like to understand why this is failing.

I am not skilled enough to fully understand the backup script. I don’t understand docker enough to know the difference between mounting an external share inside vs. outside the container. As an experiment, I tried mounting the external share to /opt/mailcow-dockerized/backup. Same behavior - tar (child): /backup/backup_mariadb.tar.gz: Cannot open: Permission denied. I also tried using the mount options you suggested, but same failures resulted.

DocFraggle

TCAtCTS However, I would like to understand why this is failing.

Well, I tried to explain that to you 😉

DocFraggle your Windows share is mounted inside the container, and then the tar command is run. This could lead to problems I guess.

You could try these mount options for your cifs share and have a look if this works better:

nounix,noperm,cache=none

^^^