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Migration of 1,000 mailboxes per day

Multiple Agent Hosts with QMM EX

Requirements of the customer

Frankfurt - Consultants of FirstAttribute AG faced an interesting challenge during a migration project in the financial service industry:

How to migrate as many Exchange mailboxes as possible to a new target environment within a few weeks?
Is it possible to migrate 1,000 mailboxes per day?

The project was realized with Dell / Quest Migration Manager for Exchang and Multiple Agent Hosts.

Requirements of the customer

The challenges of this Exchange migration were the requirements of the customer, who wanted to migrate a large number of mailboxes in a short rollout period. The project was launched due to a provider change.

  • Migration of 40,000 mailboxes to another Exchange organization
    (Roll-out within 8 weeks)
  • Interoperability between the two systems
  • Transfer of all rights and delegations
  • No restrictions for the end user
  • Automated conversion of Outlook profile

Dell / Quest Migration Manager for Exchange should be used as migration tool for this project. To meet this requirement, it was necessary to create a setting, which allows to convert at least 1,000 mailboxes per day.

The following architecture was part of the concept FirstAttribute consultants created:


○ QMM Console: Management interface and ADAM Database
○ QMM DSA Server: DirSync Process
○ QMM SQL Database: SQL Database on a shared SQL Server
○ 4 QMM Source Agent Hosts: 5 Mail-Source-Agents and 5 Mail-Transfer-Agents were provided for each Source Agent Host
○ 4 QMM Target Agent Hosts:

5 Mail-Target-Agents and 5 Calendar-Sync-Agents were provided for each Target Agent Host

Architecture of the migration



The 1,000 mailboxes per day were distributed in four Rollout groups to reduce the dependencies to a minimum. The synchronization of the data of each mailbox began 7 days before the conversion. To ensure a high data throughput, the distribution was split to 20 QMM mail-source agents and 20 QMM mail target agents (parallelization). With a lead time of 7 days, the roll out was running with an average of 4,000 mailboxes in the synchronization. As a result, only a few changes had to be transferred at the transition date, the Source mailbox had to be disabled and the target mailbox to be enabled.

The user was advised in a last e-mail that his mailbox has been moved. In that email, the user is asked, to run a program, which closes Outlook and switches the users Outlook profile automatically to the target environment. In this way, a lot of migrations per day were possible and it was ensured that the end users only had a brief interruption during their working time. 

In addition, 20 Calendar Synchronization Agents distributed on 4 Agent Hosts enabled all 40,000 mailboxes to synchronize all calendars at the same time as well.

Schematic Rollout Plan

(SW= Mailbox Switch)



By parallelizing the mailbox export and import functions on 8 servers with a total of over 60 agents and the organizational division during the rollout to multiple "migration waves" per day, all requirements have been met. All 40,000 mailboxes have been migrated within the given 8 weeks.

⇒ It is possible to migrate 1,000 mailboxes per day with Dell / Quests Migration Manager for Exchange.


Do you need support for the planning or realization of your Exchange Migration?

Please contact us if you would like to know more.


More solutions with Dell / Quest Migration Manager for Exchange here:

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