I'm not sure what you are attempting to do here. It looks like you just ran a doveadm backup and the process completed for userx with a warning that the remote system (your nfs mount) lost a particular mailbox (possibly your indexes changed or a mailbox was deleted). From the logs you pasted it appears the process completed normally.

I personally do not use dovecot's backup or replication processes. If I needed to I would use its replication process to sync active data between multiple systems, but I have no need for this as of yet. Personally I chose to create offsite backups using rsync a long time ago, as rebuilding a mailbox (reindexing) is very simple.

Try running            doveadm mailbox status -u userx guid '*'    as the mailbox administrator and see if you can find that GUID, 7e05c335174bf1608f0a02004eac7fb4. Also, see if the backup you've written to nfs has the GUID.

Well no ..I thought that dsync was for synchro " realtime for 2 different places ?

Having no 2 machines in parallel ( Just a single machine ) , I thought that a backup at regular interval  would be enough ?

So, a simple backup should be done by dsync finally ?

Do you recommend finally NOT to do a backup ( Doveadm backup ) but a replication process ? ( https://wiki.dovecot.org/Replication  ) ?

On 2/28/22 06:24, Ben Burk wrote:

Did you try running dsync?

On 2/27/22 23:15, Stephane Magnier wrote:

HI,

Any idea ? Any clue ?

On 2/25/22 21:50, Stephane Magnier wrote:

Hi

I've recently tried to use the Dovecadm backup to backup the emails..  with the following syntax

doveadm -Dv backup -u userx maildir:/mnt/nfs-backup/userx

Sounds to be OK with few emails... Some of them got a lot of emails and one f them got an error and stop !

dsync(userx): Debug: brain S: Import Trash: Import change type=expunge GUID=1725fa475d774ee19cb98dfb6737b4f1 UID=24891 hdr_hash= result=GUIDs match
dsync(userx): Debug: brain S: Import Trash: Import change type=expunge GUID=916ed110b4b1522868be6194f1ae36ff UID=24892 hdr_hash= result=GUIDs match
dsync(userx): Debug: brain S: Import Trash: Import change type=expunge GUID=eb8d75c530a7b02fc26b494d9006c91b UID=24893 hdr_hash= result=GUIDs match
dsync(userx): Debug: brain S: Import Trash: Import change type=expunge GUID=aee9155875c34861fd6500f1f2f51a26 UID=24894 hdr_hash= result=GUIDs match
dsync(userx): Debug: brain S: Import Trash: Last common UID=24894. Delayed expunges=
dsync(userx): Debug: brain S: Import Trash: Saved UIDs:
dsync(userx): Debug: brain S: Import Trash: Finish update: min_next_uid=24895 min_first_recent_uid=24895 min_highest_modseq=35344 min_highest_pvt_modseq=0
dsync(userx): Debug: /mnt/nfs-backup/userx/.Trash/dovecot.index.cache: Compressed, file_seq changed 1645803588 -> 1645803589, size=32, max_uid=24894
dsync(userx): Warning: Mailbox changes caused a desync. You may want to run dsync again: Remote lost mailbox GUID 7e05c335174bf1608f0a02004eac7fb4 (maybe it was just deleted?)
dsync(userx): Debug: auth-master: conn unix:/run/dovecot/auth-userdb: Disconnected: Connection closed (fd=10)

I empty the trash... exactly the same problem...

Any idea why this ??

Thanks and regards,