How to Manage Logs when you move bulk users between databases in Exchange Server
Moving mailboxes is a very common activity in Exchange server for large deployment scenario. When you move large number of users between different databases, You must consider the demand of extra capacity for the LUN dedicated for logs.
Move mailbox operation results a deletions record at the source database and transferred data record at the target database to the logs. If you have a higher number of mailboxes, Then the move mailbox operation will fill up the dedicated LUN for logs and cause downtime.
Following options will help you to get rid of this situation.
Option - 1: Configure circular logging
Enabling Circular logging on the target database is a easiest choice for the Exchange administrators. This will allow information service to overwrite the logs files on the file system. But logs will come to an important factor when you have a recovery activity on the database. So configuring circular logs for a long time is not a wise option. So be prepared to disable circular logging once you completed the mailbox move operation.
Option - 2: Truncate logs
Configure a backup job for exchange server database which will truncate logs once a backup job is completed. Full and incremental backup will truncate the logs but a differential or copy will not.
Option - 3: Resize your LUN
This option require more free capacity available on the raid group or storage pool which were the LUN created. If you have more capacity available on the attached SAN, then increase the log drive capacity based on the growth.