Though the number of mailboxes that can be migrated by the product concurrently is virtually unlimited, during migration process you can encounter some limitations outside the product.
In some cases, your source or target environment may not be able to keep up too many mailboxes being migrated simultaneously while still being responsive and available to their users. To avoid this problem you can limit the number of mailboxes migrated concurrently in a migration plan. Please see Limiting Concurrent Migrations for details.
Another limit you can hit is the maximum number of PowerShell connections. The product uses PowerShell to configure the forwarding options (Forwarding new items as they arrive and Turn off existing forwarding) for Exchange / Office 365. If a migration plan has one or more of these options enabled for Exchange / Office 365, when it starts, it opens a PowerShell connection to configure the enabled options. If you have too many plans configured under the same administrative account and they start approximately at the same time, you can hit the ‘PowerShellMaxConcurrency’ throttling limit for this account. In this case, the plan hit that limit will be rescheduled to start later, when a PowerShell connection is available, and the corresponding message will be displayed in the plan. Please consider to specify a different administrative account for paused plans if you need them to start immediately. Note that the connections under the same account may be done outside the product.
On Demand Migration for Email provides the following reports:
These reports are accessed by clicking Reports in the lower right corner of the Dashboard.
NOTE: For all types of reports, the value of 'Tasks/Notes" shows the sum of migrated Task and Note items.
You can download the following migration reports in the CSV format directly from the Dashboard:
The Executive Summary report shows migration statistics both at the migration plan level and the mailbox level. You can generate the report for individual migration plans or for all migration plans at once.
The Overview tab shows a pie chart representing the migration status percentages for all the mailboxes in the selected plan or plans. The total number of mailboxes in each status is displayed beneath the chart.
The Mailbox Details tab shows bar graphs representing the migration status of individual mailboxes. For each mailbox, the total number of successfully migrated items is coded green, while the total number of items that failed to migrate is coded red. By default, the Mailbox Details tab shows all the mailboxes in the selected plan or plans. To filter the results, select only the migration status options you want and click Filter.
Migration statuses include: