How to Transfer Mailboxes Between IMAP Servers with Imapsync

What is Imapsync?

Imapsync is an IMAP transfer tool used for transferring mailboxes and emails from one IMAP server to another IMAP server. Imapsync application is a command line tool that allows incremental and recursive IMAP transfers from one mailbox to another, both anywhere on the internet or in your local area network.

Installation of Imapsync

Imapsync tools is vailable for various plateform. Use one the the following tutorial as per your operating system.

• Install and Use Imapsync on Ubuntu & Debian ‎
• Install and Use Imapsync on CentOS & Fedora ‎

For installation on other platforms visit here.

Transfer Mailboxes with Imapsync

So you are ready for migration. Before migration make sure both accounts have IMAP running and accessible from your system. After that use following command syntax.

$ imapsync --host1 imap.source.example.com  \
	   --user1 [email protected] 	    \
	   --password1 S0urcePassw0rd  	    \
	   --ssl1			    \
	   --host2 imap.dest.example.com    \
	   --user2 [email protected] 	    \
	   --password2 Dest1nat10NPassw0rd  \
	   --ssl2

The command will take a long time as per the size of your source Mailbox. After completing all process, you will see a long list of output. Check the output to find if any error occurred during transfer. Below is the small part of the result.

Transfer started at Thu May 11 11:45:37 2017
PID is 4969
...
...
...
Total bytes transferred           : 78373 (76.536 KiB)
Total bytes duplicate host1       : 0 (0.000 KiB)
Total bytes duplicate host2       : 0 (0.000 KiB)
Total bytes skipped               : 0 (0.000 KiB)
Total bytes error                 : 0 (0.000 KiB)
Message rate                      : 0.1 messages/s
Average bandwidth rate            : 3.0 KiB/s
Memory consumption                : 217.0 MiB
Biggest message                   : 57947 bytes (56.589 KiB)
Memory/biggest message ratio      : 3927.0
Start difference host2 - host1    : -2 messages, -78373 bytes (-76.536 KiB)
Final difference host2 - host1    : 0 messages, 0 bytes (0.000 KiB)
Detected 0 errors

Reference:

• https://imapsync.lamiral.info/
• https://github.com/imapsync/imapsync