User Migration

Revision as of 03:04, 1 April 2006 by Bobby (talk | contribs)

Migration from one mail system to another is often painful. It can result in a user having to look in two different places to find mail, or in the worst case mail disappearing.

Copying the contents of one mail system to another often seems like a good idea, that way if anything goes wrong at least the old mail is still available. Ideally you know exactly what you are going to do at the start, you move everything across, and then you kill the old mail system (or at least make it not visible from mail clients). That way users are not confused by having two sets of identical folders.

In reality you may have to learn on the job. After user data has been migrated to Zimbra, users can access their mail via the web client without any additional setup until their mail client has been configured to access the Zimbra server.

Migrating from an existing IMAP server

Currently, the recommended method for migrating users to Zimbra from an existing IMAP server is with the imapsync tool written by Gilles Lamiral. The following guide to imapsync was originally posted to the forums by GertThiel:

Before you can use imapsync you must have both the source IMAP message store and ZCS up running and accessible to user accounts via IMAP. You can check that using an email client before starting the migration. You will need the login names (i.e. email addresses) and passwords for the users to be migrated. In addition, imapsync will not be able to authenticate to the Zimbra server until you enable clear text login for the IMAP service. You can set that option under the IMAP tab of the Global Settings or individual Server settings in the Zimbra Admin Console UI. Finally, consider that imapsync will be a heavy load on your CPU and memory; the system running the migration will be less responsive.

For this example my existing IMAP server is running on server.gtds.lan and I set up Zimbra on a new machine named zimbra.gtds.lan.

   imapsync --nosyncacls --syncinternaldates \
   --host1 server.gtds.lan --user1 yourAccount --password1 yourPassword \
   --host2 zimbra.gtds.lan --user2 yourZimbraAccount --password2 yourZimbraPassword

Of course the complete command belongs on one line (signified by the backslashes: \).

A slightly more secure method is to write each password into a seperate file, and then use the --passfile{1|2} options intead of the --password{1|2} options:

   imapsync --nosyncacls --syncinternaldates \
   --host1 server.gtds.lan --user1 yourAccount --passfile1 yourPasswordFile \
   --host2 zimbra.gtds.lan --user2 yourZimbraAccount --passfile2 yourZimbraPasswordFile

You may interrupt imapsync at any time with CTRL-C. Simply restart the same command again to resume the migration.

I used imapsync to migrate from a Cyrus IMAPd to Zimbra. The ReadMe lists a number of other IMAP servers compatible with imapsync.

Migrating from POP3

Migrating from Exchange

Migrating from Lotus Domino/Notes

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