dovecot raises Permission denied on rename of dovecut-uidlist.tmp when trying to fetch mails

[dweipert-3138720606]

I mounted the /var/mail folder to a remote cifs volume like this

services:
  mailserver:
  [...]
  volumes:
    - "remote-mail:/var/mail"
  [...]

volumes:
  remote-mail:
    driver: local
    driver_opts:
      type: cifs
      o: "addr=${REMOTE_DOMAIN},username=${REMOTE_USERNAME},password=${REMOTE_PASSWORD},file_mode=0777,dir_mode=0777"
      device: "//${REMOTE_DOMAIN}${REMOTE_PATH}"

When trying to open a folder from a mail client, like Thunderbird or aerc, I get errors like these:

Error: Mailbox INBOX: rename(/var/mail/dweipert.de/d/dovecot-uidlist.tmp, /var/mail/dweipert.de/d/dovecot-uidlist) failed: Permission denied
Error: Mailbox Sent: rename(/var/mail/dweipert.de/d/.Sent/dovecot-uidlist.tmp, /var/mail/dweipert.de/d/.Sent/dovecot-uidlist) failed: Permission denied

I can generate Drafts in the .Drafts folder for example, but not fetch a list of mails.

I tried mounting the directory within /etc/fstab and it's the same errors.
Permissions are correctly set to be world read/writable.

Any ideas what's wrong?

[polarathene]

Network mounts are not well supported by Dovecot AFAIK, at least not with the configuration we provide. You can find information about this on the Dovecot docs related to NFS, but it likely applies to SMB / CIFS too.

These operations are likely happening as the UID/GID of 5000 within the container, and I'm going to take a guess that that doesn't align with what you have for dweipert user and group in that screenshot.

You can try set the ENV DMS_VMAIL_UID and DMS_VMAIL_GID to the UID and GID values that dweipert user and group have and this will likely work.

Alternatively configure your remote to be compatible with 5000:5000 at that location used by DMS.

[dweipert-3138720606]

Thanks for your suggestions.

Somewhere in-between I tried changing the UID:GID to 5000:5000. Still got the same errors.

Regarding dovecot and network mounts, I tried applying the settings from the first paragaph here https://doc.dovecot.org/configuration_manual/nfs/ but that didn't work either.

I think what I'll do now is mount the directories on the host directly and just rsync backup everything to the remote server.
I don't have that much free space on the host, so I have to delete some old mails whenever I'm close to running out of space.

I guess that's okay. I can still search through the mails in the backup if I need to and this way the mail client might not feel that cluttered after some time as well :]