Converting user mailboxes from maildir to sdbox

[Marc Roos]

Let me know if you find a nice solution to migrate mailboxes per user, 
without downtime. I tried the use of the adviced userdb and using the 
override of the maillocation. But that doesn’t work with my mbox inbox. 


I wanted to migrate then per user to an new server environment but still 
did not find a definitive guide on how to do this. 



-----Original Message-----
From: David Mehler via dovecot [mailto:dovecot at dovecot.org] 
Sent: woensdag 22 mei 2019 2:31
To: dovecot
Subject: Converting user mailboxes from maildir to sdbox

Hello,

I've got a Postfix/Dovecot server setup. Currently Dovecot is version 
2.3.6, and it's using Maildir storage. The mailbox is:

mail_home = /home/vmail/mailboxes/%d/%n
mail_location = maildir:~/mail:LAYOUT=fs

I'm wanting to convert from Maildir to sdbox. I looked at:

https://wiki2.dovecot.org/MailboxFormat

I was initially thinking mdbox but that's multiple messages per file, 
which I do not believe is what I want. Am I correct that in the sdbox 
format if a single message file is corrupted only that message is 
corrupt and not the rest of the messages as would be the case in a mdbox 
setup?

On the page:

https://wiki2.dovecot.org/Migration/MailFormat
"
maildir -> sdbox migration. Set mail_location=sdbox:~/sdbox and run 
dsync -u username mirror maildir:~/Maildir "

If I set mail_location=sdbox:~/sdbox will that put the user mailboxes in 
mail_home/sdbox?

So it would be:

/home/vmail/mailboxes/example.com/username/sdbox

I am needing to do this migration, but am paranoid about loosing mail or 
corrupting mailboxes. All of my users are virtual users and they are 
stored in a mysql database.

Thanks.
Dave.