One Calendar Synchronization Agent (CSA) performs calendar synchronization for the mailboxes. There is one calendar synchronization job per source-target server pair. While setting up a calendar synchronization job, you are prompted to install the Calendar Synchronization Agent on either the source or target Exchange server. The Calendar Synchronization Agent synchronizes the personal Calendar folders of the mailboxes hosted on the source Exchange server with the corresponding Calendar folders of the mailboxes hosted on the target Exchange server.
A calendar synchronization job must be populated with the members it will synchronize. A mailbox can be part of a job directly or through recipient container or distribution list membership. Whenever possible, use containers to populate jobs. This will ensure that a newly created mailbox will be included in a calendar synchronization job even if it is not explicitly added.
However, if the mailboxes you plan to synchronize in a Remote Users Collection are in the same container as normal users’ mailboxes, it is better to use distribution lists to populate both the Remote Users Collections and normal collections. This will ensure that mailboxes of the remote users will not be synchronized in normal collections and vice versa.
Migration Manager for Exchange allows you to specify whether a calendar synchronization job should be one-way or two-way.
One-way calendar synchronization means that the calendar entries for each source-target mailbox pair are synchronized one way only, from the currently active mailbox to the other mailbox. An active mailbox is the source user’s Exchange mailbox until the user is switched. Once switched, the active mailbox is the target user’s Exchange mailbox. Choose one-way synchronization if mailboxes that collaborate are migrated in groups such that for each mailbox, all mailboxes it accesses will be switched at the same time.
Two-way synchronization should usually be selected, since it is difficult to migrate mailboxes in closed sets, especially when resource mailboxes are used (for example, if you represent conference rooms as mailboxes).
CAUTION: The CSA synchronizes permissions granted for the Calendar folder depending on the mailbox status.
If the mailbox is already switched, permissions are synchronized from target to source.
If the mailbox is not switched yet, permissions are synchronized from source to target.
Free/busy synchronization is performed by the Free/Busy Synchronization Agent.
While setting up a free/busy synchronization job, you are prompted to install the Free/Busy Synchronization Agent on either the source or target Exchange server.
Free/busy data resides in a public folder. In this public folder there is one message for each user that contains that user’s data. When the Calendar Synchronization Agent synchronizes appointments, the free/busy data is automatically updated.
It is often not necessary to synchronize free/busy separately from calendar data. Instead, you can increase the calendar synchronization frequency by reducing the time period during which the Calendar Synchronization Agent sleeps.
However, if you migrate users in Remote Users Collections and do not include them in calendar synchronization, which is recommended, free/busy synchronization will allow the already migrated users to see free/busy information of the users that are not migrated yet.
You need to synchronize free/busy separately only if either of the following applies:
When set to two-way synchronization, the CSA processes all mailboxes of a server for about 15–45 minutes, assuming the number of mailboxes is close to the Microsoft recommendations (approximately 1000 mailboxes per server). If you need to provide users with more up-to-date free/busy data, use one of the agents per source site to synchronize free/busy data.
While processing the free/busy synchronization job, the agent synchronizes all the free/busy messages for all the mailboxes it finds in the organizations selected for free/busy synchronization. Thus, you normally need only one Free/Busy Synchronization Agent and on free/busy synchronization job for the pair of source and target Exchange organizations.
It is important to remember that Migration Manager for Exchange does not enable multiple source Exchange organizations to have a view of the entire directory (and associated mailboxes and calendar data). Calendar synchronization will enable all target Exchange users to view and modify all calendar data. The users connecting to mailboxes in the source Exchange organizations will continue to have access to calendar data for users in their organization, whether those users are switched or not. However, users connecting to the source Exchange organization will not be able to see calendar detail data for users that were migrated from other source Exchange organizations.
The following are the important items to consider regarding mailbox switching and profile updating: