System Mailbox / Arbitration Placement in Exchange 2013

Typically within an Exchange organization - when it is initially setup the relevent arbitration mailboxes are created e.g. your System Mailboxes.

By default only one system mailbox is created on your first database - this is fine - however if you need to perform maintainence on this database it effectively takes the system mailbox out-of-action. So as a reccomendation I would be enclined to create a dedicated mailbox database (or at least one which is unlikely to need regular maintainence) to host the system mailboxes.

To view the current arbitration mailboxes and the databases they are situated on we can issue:

Get-Mailbox -Arbitration | fl name, alias, database

You can also simply move your current arbitration mailboxes another database as follows:

Get-Mailbox -Arbitration -Identity "SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}" | New-MoveRequest -TargetDatabase MailboxDatabase01