Microsoft Exchange Server 2010 : Creating and Managing Database Availability Groups (part 2) - Managing Availability Group Membership

2. Managing Availability Group Membership

When you add a server to a database availability group, the server works with the other servers in the group to provide automatic, database-level recovery from database, server, and network failures. To be included in a database availability group, a server must be running Windows Server 2008 SP2 Enterprise or later or Windows Server 2008 R2 or later and must have at least two network interface cards. Each network interface card must be on a different subnet.

Note

Each server that you want to add to the database availability group must have two network adapter cards. The first network adapter, referred to as the replication adapter, handles replication traffic, and the second adapter, referred to as the messaging adapter, handles MAPI network traffic and other traffic originating outside the replication network.

Keep the following in mind when planning database availability group membership:

• If you created the availability group using the Exchange Management Console and want to add servers to the group by using the Exchange Management Console, at least one of the server's network cards must be configured to use Dynamic Host Configuration Protocol (DHCP). When you add the first Mailbox server to the database availability group, the group must be assigned an IP address. By default, Exchange uses DHCP to obtain an IP address for the group. This IP address becomes the IP address for the group. Alternatively, you can create the group by using the Exchange Management Shell. Use New-DatabaseAvailabilityGroup and set the IP address using the –DatabaseAvailabilityGroupIp parameter.

• If you no longer want a server to be a member of a group, you can remove it from the group and the server will no longer be automatically protected from failures. Keep in mind that you must remove all replicated database copies from a server before you can remove it from a database availability group.

• If you didn't create the group and set its IP address by using Exchange Management Shell and DHCP is not available in your organization, or if you want to use a static IP address for an availability group, you can use the –DatabaseAvailablityGroupIpAddresses parameter of the Set-DatabaseAvailabilityGroup cmdlet to specify a static IP address for the group prior to adding servers. The IP address is needed prior to adding the first Mailbox server to the group.

You can add a Mailbox server to or remove a Mailbox server from a database availability group by completing the following steps:

1. In the Exchange Management Console, expand the Organization Configuration node and then select the related Mailbox node. In the results pane, select the Database Availability Group tab to view existing availability groups, as shown in Figure 2.

   

   Figure 2. View configured database availability groups.

2. Right-click the database availability group you want to work with and then select Manage Database Availability Group Membership. On the Manage Database Availability Group Membership page, shown in Figure 3 you can

   • Click Add to add a server to the database availability group. In the Select Mailbox Server dialog box, select one or more servers and then click OK.

   • Select a server from the list of current members, and click the red X to remove the server from the database availability group.

3. Click Manage to apply your changes. On the Completion page, the Summary states whether the operation was successful. If an error occurred, you need to take the appropriate corrective action. Otherwise, click Finish.

Figure 3. Add or remove group members.

In the Exchange Management Shell, you can list database availability groups using Get-DatabaseAvailabilityGroup. If you enter Get-DatabaseAvailabilityGroup without additional parameters, you'll see a list of all availability groups in the current Active Directory forest as well as the member servers and operational servers for those groups, as shown in the following example and sample output:

Get-DatabaseAvailabilityGroup


Name            Member Servers              Operational Servers
----            --------------              -------------------
EastCampusDAG1  MailServer25, CorpServer27  MailServer25, CorpServer27
WestCampusDAG1  MailServer44, MailServer18  MailServer44, MailServer18

Use the –Identity parameter to specify the name of the database availability group to query. Add –Status to any query to include real-time status information.

You add or remove group members using Add-DatabaseAvailabilityGroupServer and Remove-DatabaseAvailabilityGroupServer. Samples Example 1 and Example 2 provide the syntax and usage.

Example 1. Add-DatabaseAvailabilityGroupServer cmdlet syntax and usage

Syntax

Add-DatabaseAvailabilityGroupServer -Identity DAGName
-MailboxServer ServerToAdd
[-DomainController FullyQualifiedName]


Usage

Add-DatabaseAvailabilityGroupServer -Identity "EastCampusDAG1"
-MailboxServer "MailServer62"

Example 2. Remove-DatabaseAvailabilityGroupServer cmdlet syntax and usage

Syntax

Remove-DatabaseAvailabilityGroupServer -Identity DAGName
-MailboxServer ServerToAdd
[-ConfigurationOnly <$true | $false>]
[-DomainController FullyQualifiedName]


Usage

Remove-DatabaseAvailabilityGroupServer -Identity "EastCampusDAG1"
-MailboxServer "MailServer62"

If a Mailbox server has failed and cannot be recovered, you can recover operations in one of two ways:

• You can use the Remove-DatabaseAvailabilityGroupServer cmdlet to remove the configuration settings for the Mailbox server from the database availability group. After you remove the configuration settings, all settings associated with the Mailbox server are gone.

• You can install Exchange on a server that has the same name and domain membership as the old server and use Exchange Server 2010 Setup with the /m:RecoverServer switch. Running Setup with the /m:RecoverServer switch causes Setup to read the failed server's configuration information from Active Directory. After Setup gathers the server's configuration information from Active Directory, Setup installs the original Exchange files and services on the server, restoring the roles and settings that were stored in Active Directory.