Re: [EXT] Re: postfix/dovecot migration

> On 16/05/2026 21:15 EEST Bryan Simmons via dovecot <[email protected]> wrote:
> 
>  
> Was able to execute the process as root with "doveadm -D backup -Ru tst tcp:10.0.1.212:12354" after updating some destination side configuration options that do not appear to be documented in the link provided, but there are a few errors that I am unable to understand or correct.
> 
> 1. Debug: open(/proc/self/io) failed: Permission denied - This file is read only for root and permissions cannot be modified.

You can ignore this, it's a debug message. It's only relevant if you need io statistics.

> 2. Error: Mailbox INBOX sync: mailbox_delete failed: INBOX can't be deleted. - Not sure why a mailbox would need to be deleted other than the backup is using a delete and recreate to retain only current emails, assuming this is on the destination server.
> 3. All emails for tst account are deleted from the source server - This is a significant issue when only copies should be made for a backup.
> 
> Full log is attached.
> 
> Any additional insights would be greatly appreciated, Bryan
> 
> 

I'm guessing you ran the backup command on source server. You should not use -R then, only use -R if you use it from destination server.

doveadm backup copies *from* account *to* target. If you use -R it will copy *to* 
account *from* target*.

Hope this helps.

Aki

> May 15, 2026 10:01 AM, "Aki Tuomi" <[email protected]> wrote:
> 
> > Yeah, you can do migration with dsync or imap between 2.3 and 2.4
> > 
> > Aki
> > 
> >> On 15/05/2026 16:10 EEST Bryan Simmons <[email protected]> wrote:
> >> 
> >> Aki,
> >> 
> >> Thank you for the guidance.  Just to confirm, doveadm/imap based
> >> migration is the section under "Migrating Mailboxes from Another Dovecot
> >> Server" in the link referenced below since this migration will be
> >> between servers?
> >> 
> >> Seems an upgrade from dovecot 2.3.21 (current version on source server) 
> >> to 2.4.2 (installed version on the destination server) would be
> >> appropriate before migrating any user accounts based on information from
> >> some of the other posts regarding migration.
> >> 
> >> Thanks , Bryan
> >> 
> >> On 5/13/26 13:41, Aki Tuomi via dovecot wrote:
> >> On 13/05/2026 20:31 EEST Bryan Simmons via dovecot <[email protected]> wrote:
> >> 
> >> Moving postfix and dovecot to a new server including all current users
> >> and emails.  There exists several dovecot files in each user mail directory:
> >> 
> >> dovecot.index
> >> dovecot.index.cache
> >> dovecot.index.log
> >> dovecot-keywords
> >> dovecot.list.index.log
> >> dovecot.mailbox.log
> >> dovecot-uidlist
> >> dovecot-uidvalidity
> >> dovecot-uidvalidity.612d3d34
> >> 
> >> Should these files be migrated also or will dovecot recreate them as needed?
> >> 
> >> Thank you, Bryan
> >> 
> >> https://doc.dovecot.org/2.4.4/core/admin/migration.html#migrating-mailboxes
> >> 
> >> I would recommend seeing this. Depending on your mailbox format, it can be important that those
> >> files are copied, but I would suggest doveadm/imap based migration.
> >> 
> >> Aki
> >> 
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