Title: Convert mailbox to maildir with dovecot

	Title: Convert mailbox to maildir with dovecot
	Author: Solène
	Date: 17 January 2017
	Tags: unix email
	Description:

	I have been using mbox format for a few years on my personal mail
	server. For those who don't know what mbox is, it consists of only one
	file per folder you have on your mail client, each file containing all
	the mails of the corresponding folder. It's extremely ineficient when
	you backup the mail directory because it must copy everything each
	time. Also, it reduces the system cache possibility of the server
	because if you have folders with lots of mails with attachments, it
	may not be cached.

	Instead, I switched to maildir, which is a format where every mail is
	a regular file on the file system. This takes a lot of inodes but at
	least, it's easier to backup or to deal with it for analysis.

	Here how to switch from mbox to maildir with a dovecot tool.

	# dsync -u solene mirror mbox:~/mail/:INBOX=~/mail/inbox

	That's all ! In this case, my mbox folder was ~/mail/ and my INBOX
	file was ~/mail/inbox. It tooks me some time to find where my
	INBOX really was, at first I tried a few thing that didn't work and
	tried a perl convert tool named mb2md.pl which has been able to
	extract some stuff but a lot of mails were broken. So I have been
	going back getting dsync working.

	If you want to migrate, the whole process looks like:

	# service smtpd stop

	mail_location = mbox:~/mail:INBOX=/var/mail/%u # BEFORE
	mail_location = maildir:~/maildir # AFTER

	# dsync -u solene mirror mbox:~/mail/:INBOX=~/mail/inbox
	# service smtpd start