Guidelines to Migrate to Zoho Mail

Process Overview

1. Add domain(s) in Zoho Mail.

2. Verify domain(s) in Zoho Mail.

3. Create all users and groups in Zoho Mail.

4. Create batches of Migration with <nnn> users in each batch.

5. Run sample migration for 3 or 4 users to test the migration.

6. Ideally, a weekend is suitable to switch the service (low incoming emails).

7. Inform the users about the switch of email and provide the login details for the users before the switch.

8. Change the MX to Zoho Mail. (Friday night/ Saturday early morning).

9. Email Routing can be configured to avoid any loss of data.

10. Run IMAP migration for all batches of users selecting Office 365 for the server info one by one.

11. Create a catch-all account (not applicable in case of Split Delivery) to monitor and find out if any email addresses (groups/ users) were missed when creating the users. 

Best Practices

1. Run a sample migration for around 2 to 10 users before the actual migration process.

2. This will help us know the source server behavior (user limit, mail size limit, speed of migration etc.)

3. The sample users mailboxes should be migrated again to fetch the emails that got delivered before changing the MX. Duplication will be handled at our end.

4. Alternately, you can also set a date limit while adding the final migration for the sample users’ mailboxes to ensure that all emails after the sample migration have been migrated.

5. The maximum connection limit is the number of connections accepted by a server at a given time. Set the maximum number of connections depending upon the server load and the number of users.

6. Some servers will throttle the data fetch in IMAP after a certain interval. After that, the mail fetching for migration will be slow to avoid the real-time mail traffic.

7. While setting up migration for a batch of users, set the priority for each user. Users whose priority is as ‘1’ will be treated as the highest priority, will be migrated first, and the rest will follow according to the priority set, and the rest will follow.

In general, to complete a migration for a batch of 25 users, each with a mailbox size of around 2 GB, and the maximum Connection Limit set to 10, it approximately takes 11 hours.