Exchange 2013 Mailbox Server Role in Short

This is a short note on Mailbox Server Role in Exchange Server 2013. If we look at Exchange Server 2010 mailbox server role, it hosts the mailbox database and public folder database. Exchange Server 2013 also host the mailbox databases and the Public Folders (not the Public Folder Database) inside the mailbox databases and the activities like data storing, processing and rendering will takes place in Mailbox Server role itself.

Below are some of the important changes\options that are available in Exchange 2013 Mailbox Server Role

Mailbox Server Role Connection:


In Exchange 2010 all the client connection goes via the Client Access Server and the Client Access Server will connect to the mailbox server to access the mailbox data but the folder access will directly goes to Mailbox Server role. In Exchange 2013, the only server role that directly connects to Mailbox Server role is the Client Access Server and all the Clients connection goes Client Access Server Role. There is an exception on the UM call routing, where the UM client send a SIP request hit the UM component on the CAS and it will send a SIP redirection to call and the caller will connect to Mailbox Server.

Changes to Public Folder Database:


Public Folder database are no longer available with Exchange 2013. It doesn't mean the public folders are removed, we can continue to use the Public Folders using the newly created Public Folder Mailbox. First created Public Folder Mailbox will hold the Public Folder Hierarchy and there won't multi master replication model, Exchange Server 2013 Public Folders will continue to use the same Continuous Replication model to achieve high availability.

Separate Process for each Mailbox Database


With the newly introduced managed stored model, every mailbox database will have a separate process. If any issue with the single mailbox database, then that particular process will go down and there won't be any issue for the other mailbox databases.

High Availability for Mailbox Server


Exchange 2013 has the function of Database Availability Group which is available in Exchange 2010. DAG allows having 16 Mailbox Server to be member of DAG and the DAG is boundary for replication of Mailbox Databases. We can create 100 Mailbox databases per server including the active and passive mailbox database. DAG uses the same continuous replication model to replicate the active mailbox databases to passive mailbox database.

Support for larger Mailbox


Exchange 2010 supports up to 25 GB of Mailbox size, with Exchange 2013 it supports up to 100 GB of Mailbox size this removes the need for third party archive solutions and we have the option to control the size of the Offline Storage file (OST) using outlook 2013

Mailbox Server role as Transport server


Mailbox Server role in Exchange Server 2013 performs a transport functionality of email. There are 3 important services running in Mailbox server role that handles the mail flow, they are

• Microsoft Exchange Transport – handles mail flow and performs content inspection


• Microsoft Exchange Mailbox Transport delivery – it will receive email from Microsoft Exchange Transport Service and delivers it to Mailbox database


• Microsoft Exchange Mailbox Transport Submission – this is the mailbox submission service in exchange 2010, which will take the mail from mailbox database and submits it to Microsoft Exchange Transport service.

Other lot of features like faster mailbox search, IOP reduction to 99.7 % and lot of improvements on the mailbox database high availability and resilience are done in Exchange server 2013.

If you need any information on the mailbox server role on Exchange Server 2013, leave your comments here.