Overview:
Cloudiway’s mail migration solution helps businesses perform elaborate technical migrations through a simple SaaS interface. As a result, mail migrations require no additional software installation or overhead, and migrations can be performed securely and quickly.
The Cloudiway platform is flexible enough to support all types of migration paths. Your migration strategy will depend on your business setup, type and size. Whichever migration path you choose, Cloudiway provides all the essential features including license assignment, archive migration, mail routing and calendar coexistence (free/busy scheduling).
Two of the most common migration strategies are cutover and staged migrations. Cutover strategies involve migrating all mailboxes over a weekend, ready for your users on Monday morning. Staged strategies provide more flexible migration options, as discussed below.
1.1 Cutover migration
You migrate everybody over a weekend and perform a single migration pass. This strategy is the simplest to implement. After you have switched your MX records to point to the new system, you start mailbox migration.
Cutover migration is, therefore, a strategy where the entire company is switched at the same time.
1.1.1 Cutover migration benefits
1.1.2 Cutover migration considerations
You can combine your cutover migration with pre-staging if required. In this case, during the days or weeks leading up to your cutover, you would migrate all emails up to a week or so ago along with calendars and contacts, then on the day of your cutover, you would run a quick delta pass to migrate the remaining items.
1.2 Staged migration
A staged migration allows you to migrate batches of mailboxes over the course of a few weeks or months. This strategy is useful for migrations with large volumes of data (very full mailboxes or many mailboxes) and you estimate that you won’t be able to do your migration over a single weekend.
Cloudiway offers you additional flexibility in your approach to a staged migration. For example, you could migrate the last six months of emails over a weekend and leave older emails and email archives to be migrated after cutover, explaining to users that their older emails will appear soon.
Prestaging is also an option on the Cloudiway platform. For example, you could perform a multi-pass migration where you migrate most mailbox items before performing the final cutover. During the days or weeks leading up to your cut-over, you would migrate all the mails up to a week or so ago along with calendars and contacts, then on the day of your cutover, you would run a quick delta pass to migrate the remaining items.
Cloudiway provides a number of options to help you find the best strategy for a staged mail migration. We provide coexistence services, plus mail routing, and batch migration of users, which you can define in any way you like. Basically, you can choose who, when and what gets migrated during each pass.
1.2.1 Staged migration benefits
1.2.2 Staged migration considerations
Staged migrations tend to be more complicated than single cutover migrations. Therefore, it’s important that you have planned your approach thoroughly prior to starting any migration.
1.3 Supplementary tools
Cloudiway has developed a number of tools to enable seamless migration for the most intricate migrations. Our supplementary tools include:
These tools are available as additional modules, and therefore incur an extra cost. Please contact us for more information.
1.3.1 Calendar free/busy and GALSync
Cloudiway provides a coexistence suite for calendar free/busy display and GALSync. For example, a G Suite user on one can check the free/busy time of an Office 365 user. It also creates all users as contacts both sides and keep the address books up to date. Coexistence manages cross-platform communication with no impact on the end-user. It provides a seamless connection between two different remote systems during the migration.
1.3.2 Mail routing
If you wish to migrate a domain name from one Office 365 tenant to another, you face some challenges. A domain can only be attached to one Office 365 tenant, and detaching a domain from a tenant is complex and time-consuming: no mail addresses referencing the domain can remain. Furthermore, the domain cannot be reattached until it’s completely detached from the first tenant, which can take up to two days. Cloudiway provides a mail routing platform that routes mail automatically and transparently from source domains to target domains. Please get in touch to discuss what options are available.
For more information about security, please refer to this article.
For more information about migration performance, please refer to this article.
4.1 What can be migrated
When migrating from one Office 365 tenant to another, all of the following mail-related items can be migrated:
4.2 Migration limitations
Domain name migration between Office 365 tenants can be tricky: the domain name can only be attached to one Office 365 tenant at a time, so during a typical migration, it would remain unavailable for two days and mail delivery would be affected.
However, Cloudiway provides a solution that makes the transition trouble-free. Cloudiway’s mail routing platform enables emails to continue to be received and delivered to the correct inboxes during a domain name change. Mail headers are not modified.
Once you’ve pointed your MX records to our mail routing platform, it will deliver incoming mails to the target domain of your choice (ie, targettenant.onmicrosoft.com). You then detach the domain from your source tenant, and once it’s completely detached you attach it to the target tenant, point your MX records to the target Office 365 tenant and stop using the Cloudiway mail routing platform.
The mail routing service is not available by default, so if this functionality interests you, please get in touch for more information and a quote.
During migration, Outlook profiles are not recreated. Cloudiway provides a tool to perform this if you need help.
4.3 Considerations
There are several important factors that you should be aware of before starting a mail migration.
Firstly, migration takes place between existing mailboxes. This means that mailboxes must exist in the target at the time of migration. Please ensure that all mailboxes to be migrated have had their target mailbox created in the target domain (steps are included in this guide). If required, you can use the optional IAM module to provision the target.
Secondly, to migrate a user, you must provide the primary source SMTP address and the primary target SMTP address. If you specify an alias, the mailbox migration will fail.
Finally, if you decide to use Cloudiway’s mail routing platform during your migration, please refer to Cloudiway’s mail routing documentation before you begin your migration to ensure you fully understand what you need to do before and after a migration for an uninterrupted flow of emails.
4.4 Audience
This guide is aimed at experienced system administrators who are capable of connecting to remote systems and using a variety of administration tools.
Although we provide support for our own products, we do not provide support for third party products such as PowerShell or server administration of Google or Exchange.
If you are concerned you might have any difficulty completing these steps, please consider a solution with our consulting team, contactable via presales@cloudiway.com. This will ensure a fast, costeffective and stress-free implementation.
5.1 Before you start
Before you start, you will need to ensure you have the details outlined in the following table.
| Name | Name | Location |
| Cloudiway login | Stores details and provides communication between the systems you already use. | https://apps.cloudiway.com |
| Knowledge base access | Our extensive knowledge base is always accessible, with videos, troubleshooting tools, samples and more. | https://kb.cloudiway.com |
| Office 365 account with impersonation privileges | Used for impersonation to access mailboxes (read or write). This doesn’t have to be the tenant’s admin account. However, it must be an administrator account if you wish to migrate the permissions. The account must be able to bypass SSO and authenticate using username/password credentials with the format: user@tenant.onmicrosoft.com (with a password set to never expire). | We recommend you create a non-federated domain account (on your *.onmicrosoft.com domain) especially for migration. After all migrations are complete, simply delete this account. We provide steps below to help you set up an account with impersonation privileges if you don’t already have one. |
Deactivate MFA On Your Office365 Migration Account (guide: https://kb.cloudiway.com/article/deactivate-mfa-on-your-office365-migration-account/).
5.2 Set up an Office 365 account with impersonation privileges
An account with impersonation privileges can access up to 100 mailboxes concurrently. Therefore, by default, Cloudiway allows you to migrate 100 concurrent users. If you wish to speed up your migration, you should set up additional Office 365 connectors (both source and target) on the Cloudiway platform and associate different accounts with admin access to each one.
Below are the steps to show you how to set up impersonation using the Office 365 Exchange Admin Center. If you don’t already have impersonation set up, please follow the steps below.
5.3 Recreate your shared mailboxes (using provisioning)
Cloudiway provides a tool to provision resources, as well as scripts to provision shared mailboxes and reset permissions on them. The tool is available on the Cloudiway migration platform and will be covered later in this guide. This section covers shared mailbox provisioning.
To run the scripts, you will need to use Windows PowerShell. You should check that you have high enough access on your PC to run scripts and a basic working knowledge of PowerShell.
The scripts can be downloaded in zipped format from the Cloudiway knowledge base article, which contains full details and examples of script output, plus the correct running order of the scripts, here:
6.1 Create your source and target connectors
For Cloudiway to migrate your email, it needs to be able to communicate with both your source and target domains. To do this, Cloudiway uses connectors, which are configured on apps.cloudiway.com. You will need to set up a connector for each source tenant you wish to migrate and each target tenant that mail should be migrated to. Follow the steps below to configure Office 365 connectors.
Remember, each account with impersonation privileges can access up to 100 mailboxes concurrently. Therefore, by default, each Cloudiway connector can migrate 100 concurrent users. If you wish to speed up your migration, you should set up additional Office 365 connectors (both source and target) on the Cloudiway platform and associate different accounts with admin access to each one.
6.2 Create a partial archive from a normal inbox
Creating a partial archive of emails provides a number of benefits. From a migration perspective, the biggest benefit is reduced bandwidth. End-users who access mail via Outlook have their mailbox locally cached (in .ost file format). After a mail migration, Outlook will download all migrated mailboxes the first time users access their mailboxes. Therefore, if many users are likely to access Outlook at around the same time after migration (for example, if you’ve completed a cutover migration one weekend before staff arrive at 9am Monday morning), your bandwidth might slow down due to a glut of downloads.
This can be avoided by partially migrating data to the online archive. For example, you could choose to migrate all items older than 30 days to a mail archive, which would be performed prior to the final cutover. The data will remain online and accessible from each user’s inbox as an In-Place Archive
folder. The most recent 30 days of emails will be migrated and downloaded when each user first logs in, reducing overall bandwidth usage due to smaller mailbox sizes.
Note: you must ensure that In-Place archiving is switched on within your Exchange Admin center (you can bulk-activate using the instructions on TechNet as https://technet.microsoft.com/enus/library/jj984357(v=exchg.150).aspx).
In-Place archives at the source are treated differently to standard mail and are not migrated by default. You can buy a mail archive quota package to perform an archive migration (see section 7.2).
6.3 Configure the global settings for migration
Now that you have set up at least one source and target connector, you’re ready to configure your global settings. Using the Cloudiway platform, this is simply a matter of selecting what you want to migrate.
By default, the global migration settings are configured to migrate everything but the Trash folder. You can toggle these and change the date and time settings from the Global Settings option on the Cloudiway platform.
Most of the options are self-explanatory. The Convert Email Address option needs further explanation. When activated, this option rewrites email addresses found in the header and replaces source email addresses with their corresponding target email addresses.
For example, if Bob sends an email to his colleague to Chloe from his source address bob@source.com to chloe@source.com and a week later, after migration, chloe@target.com replies to Bob, the Cloudiway platform has already updated SMTP header in Bob’s original email in her inbox, so her reply will be sent to bob@target.
For migrations where the only email address change is the domain name (such as Bob’s email address above), the Cloudiway platform uses the domain name defined in the target connector to convert source email addresses.
For migrations where both the domain name and the username change (for example, bob@source.com becomes newbob@target.com), the Cloudiway platform already uses a mapping table to link each user. This mapping table is also used by the Convert Email Addresses option in this situation. Therefore, it’s important that all users exist in the mapping table before migration begins (this guide contains instructions).
Note that users in the mapping table do not require a license until you’re ready to migrate them. Therefore, you can assign the free ‘No license’ option to all your users prior to migration. Having a complete mapping table is also required if you plan to use Cloudiway’s free/busy calendar tool in conjunction with mail migration.
The Convert Email Address option is switched on by default (and is best left on). Make sure your user list is up to date to benefit from this functionality.
X.500 address migration
The Cloudiway platform automatically converts any X.500 addresses to SMTP during the mail migration.
However, X500 entries are not converted during the calendar migration. It’s necessary to migrate the LegacyExchangeDN. If you do not migrate the LegacyExchangeDN, your users will not be able to modify their calendar entries after the migration.
Please follow this article to know how to migrate the LegacyExchangeDN.
This task can be done at any time of the project. However, the best practice is to do it before the migration.
6.4 Import or create your users
There are a number of ways to add users that you wish to migrate. These include:
Regardless, each user will need to be assigned a license type — Trial (limited to 100 MB), Education, Standard, Archive, or No License (used for adding users to your mapping table regardless of migration plans).
6.4.1 Option 1: CSV import
If you have a CSV file of all your users, you can upload the file to Cloudiway. The file must have the following fields in the header row:
FirstName;LastName;SourceEmail;TargetEmail;BatchName
Note that many browsers limit CSV file uploads to 5000 lines, so files larger than that should be split up and uploaded separately. Data already uploaded will not be overwritten, so you can upload as many files as required.
The BatchName field can be left blank. If required, you can use this field to name different batches so they can be run in a certain order. A sample CSV file is available for download during the steps outlined below.
6.4.2 Option 2: Import Users tool
Cloudiway’s Import Users tool helps you to retrieve users from your source tenant. The functionality works via Identity Access Management. The tool requires you to specify any transformation rules you wish to apply. It will then add new users in the Mail Migration User List view within the Cloudiway platform.
This is an advanced tool that is best used in partnership with Cloudiway consultants. If you are interested in using this option, please get in touch with your Cloudiway contact.
Many of our first-time customers create a single user for testing purposes. This provides a means of watching the migration process without affecting all users. Single users can also be created for migrations affecting just a few users.
6.5 Recreate your resources (using provisioning)
The Cloudiway platform provides a free resource creation tool to customers performing mail migrations between Office 365 tenants. Recreate rooms and equipment using the steps below.
6.6 Activate and monitor your migration
Now that you have performed all the pre-migration steps within your tenants and within Cloudiway, you’re ready to migrate. We recommend you run a test migration on a single user first to check that your configuration produces the outcome you expect.
To start your migration, select the users or batch you wish to migrate and click on the Start button. Your batch will be scheduled and will begin as soon as resources are available. By default, a hundred migrations can be run concurrently per connector.
Don’t forget that Cloudiway migration platform supports delta passes and that migrations are therefore incremental; every time you restart the migration of a mailbox, only items that haven’t already been copied to the target will be migrated. The platform therefore does not duplicate items in the target.
6.7 Migrate permissions globally
You can globally migrate permissions for mailboxes through the Cloudiway platform.
NOTE: Once you start the process of setting permissions, it cannot be stopped.
7.1 Migrate a domain name between tenants
Remember, a domain name can only be attached to one Office 365 tenant at a time, so during a typical migration where the domain name is moved from the source to the tenant, it could remain unavailable for up to two days and mail delivery would be affected.
However, Cloudiway provides a solution that makes the transition trouble-free. Cloudiway’s mail routing platform enables emails to continue to be received and delivered to the correct inboxes during a domain name change. Mail headers are not modified.
Once you’ve pointed your MX records to our mail routing platform, it will deliver incoming emails to the target domain of your choice (ie, targettenant.onmicrosoft.com). You then detach the domain from your source tenant, and once it’s completely detached you attach it to the target tenant, point your MX records to the target Office 365 tenant and stop using the Cloudiway mail routing platform.
The mail routing service is not available by default, so if this functionality interests you, please get in touch for more information and a quote.
The following steps explain how to transfer a domain name between two Office 365 tenants. They require the use of administration tools such as AD Sync and PowerShell. Remember, Cloudiway does not provide support for the use of these products, so if you don’t have the required experience, please contact Cloudiway who can put you in touch with expert partners to assist you.
| Source SMTP | Target SMTP |
| company1.com | target.onmicrosoft.com |
| company2.com | target.onmicrosoft.com |
Once you’re certain that all references to the domain have been removed, you’re safe to detach it.Your Cloudiway mail migration has now been completed (but other administrative migration tasks might still exist). Cloudiway cannot provide post-migration reconfiguration advice about your AD Sync environment or client computers. If you need further help with these, we have a range of partners who can work with you, depending on your needs. Please get in touch via sales@cloudiway.com.
For your convenience, Cloudiway does provide a tool to create new Outlook profiles. If you would like to use this product, please get in touch.
7.2 Migrate existing archive mailboxes
Office 365 In-Place archive folders can be migrated between tenants. These folders are not migrated during standard mail migration.
Office 365 archives can be entirely migrated to the In-Place Archives folder within an Office 365 inbox or directly to an inbox, or a mixture of both. Cloudiway requires a special archive license to ensure archive mails are migrated from the source In-Place archive to the correct target. (You can buy archive packages the same way you buy a standard user license for Cloudiway, or you can contact us at sales@cloudiway.com to request archive packages.)
The Cloudiway platform ignores In-Place archives during standard mail migration. During archive migrations, the platform ignores everything but In-Place Archive folders, so there’s no risk of other inbox items being migrated.
The most straightforward way to migrate archives is to create a new target connector to use especially for archive migrations. This allows you to begin an archive migration even if a user’s inbox migration is ongoing.
For example, the following steps are required to migrate a user who has an inbox and an archive:
If you have followed this user guide, you will have already performed steps 1, 2 and 3. You can now perform steps 4 to 6 for the archive migration.
For example, if Bob has a normal mailbox and an In-Place archive, he will appear on the Cloudiway platform twice: once in the standard User List section and once in the Archive user list section. Bob’s entry in the User List section will be associated with the standard mail migration connectors you set up in steps 1 and 2. Bob’s entry in the Archive user list section will be associated with the archive target connector you set up in steps 5.
As these two migrations are treated separately, you have the flexibility to migrate archives before, during or after the standard mailbox migration has taken place. If you choose to migrate both at the same time, ensure that you provide different admin credentials for each target connector, and consider duplicating the source connector with different admin credentials so the migration is not limited by throttling on a single account.
Cloudiway provides an extensive knowledge base with many resources, including common error messages, video guides and downloads.
Please visit the entire knowledge base here (where you can search for keywords or read through topics): https://kb.cloudiway.com/
The knowledge base also contains information on how you can ask for further support, should you require it.
