Exchange Server 2010 Client Access Server Backup and Recovery

The Exchange Server 2010 Client Access Server role is responsible for client connectivity to mailboxes.  All client connection methods are provided by the Client Access server, including:

• MAPI (eg connecting via Outlook on the LAN)
• HTTPS (eg Outlook Web App, ActiveSync, or Outlook Anywhere)
• IMAP
• POP3

The only client connections to Mailbox server resources that the Client Access server does not provide are Outlook clients connecting to Public Folder databases.  Outlook connects directly to the Mailbox server for public folders.

What Needs to be Backed Up on Client Access Servers?

To plan for backup and recovery of the Client Access server you should start by knowing where the server stores its configuration and data.

Active Directory – the majority of the Client Access server configuration is stored in Active Directory.  For example the internal and external URL settings of the OWA virtual directory are stored in Active Directory.

However not all of the settings for these Client Access server features are stored in Active Directory.

System State – the system state of the Client Access server stores important information such as the SSL certificates installed on the server, and service configuration information (eg dependencies and startup options).  If the server is a member of an Exchange 2010 CAS array the NLB configuration is also stored in the system state.  Finally if there are other applications installed on the server then those will likely have settings stored in the registry as well.

File System – because of the Client Access server’s integration with IIS there are multiple configuration files stored on the file system itself for components such as the OWA virtual directory.  The IIS root config file (aka the IIS metabase) is also stored in the file system.

Planning the Client Access Server Backup

As you plan the Client Access server backup strategy there are different techniques that you can consider depending on your requirements.

Backing up Everything

A full system backup of the Exchange 2010 Client Access server, along with a working Active Directory, will have all of the required information to recover the Client Access server.  Naturally this backup takes the longest to run, and will use up the most backup storage.

Backup up the Minimum

To reduce backup storage and keep the backup time frame shorter the minimum data on the Client Access server can be backed up.  This involves backing up the system state of the server, and configuration files stored in the ClientAccess path of the Exchange Server 2010 installation folder (C:Program FilesMicrosoftExchange ServerV14 by default).

Backing up Nothing

It may be practical to not back up the Client Access server at all if:

• There are multiple, redundant Client Access servers deployed (ie Client Access Server Array)
• The SSL certificates are exported or retrievable from elsewhere
• Customizations to the Client Access server virtual directories can be quickly reapplied using an existing script

If all of those conditions are true then the Client Access server may not need to be backed up at all.

Backing Up and Restoring Client Access Servers

In this demonstration a Client Access server has been configured as a single-node NLB cluster and Exchange 2010 CAS array.

The external URL has also been configured.

Recovering an Exchange 2010 Client Access Server

Because most of the Client Access server configurtion is stored in Active Directory when a Client Access server has failed you can recover the server using the following procedure.

1. Install a new server to host the Client Access server role
2. Configure the server to have the same name, IP address, and domain membership as the server that failed
3. Install the Exchange Server 2010 pre-requisites
4. Perform a recovery mode install of Exchange Server 2010

To run Exchange Server 2010 setup in Recovery Mode use the following command from an elevated command prompt.

Setup performs a server recovery using the configuration information stored in Active Directory.

After the reboot you can verify that some configurations have been recovered, such as the OWA virtual directory URLs. However any other customized configurations that were stored in the system state or the file system are not recovered by this process. Those settings will need to be reapplied from the minimal backups, or reapplied manually or by using a script.

Full System Backup/Restore for Exchange 2010 Client Access Servers

For this demonstration I used Windows Server Backup to perform a full system backup of the Client Access server for use in a bare metal restore.

Even though this Exchange Server backup can take the longest it is the simplest to restore from because it will restore the Client Access server as it was at the time of backup.

Summary

You can see there are positives and negatives to the backup strategies for the Client Access server role in Exchange Server 2010.  For most organizations the full backup/restore method will be the simplest to implement and maintain.  Larger environments with multiple Exchange 2010 Client Access servers may prefer to backup the minimum instead, or even backup nothing at all, and rely on redundancy to keep services up while the Client Access server is recovered and reconfigured manually or via scripts.

Back to the full series on Exchange Server 2010 backup and recovery.