Exchange Server 2010: Deploying Exchange Databases (part 2) - Managing Mailbox Databases

2. Managing Mailbox Databases

A mailbox database is an Exchange database for storing mailboxes. It manages the data in mailboxes, tracks deleted messages and mailbox sizes, and assists in message transfers. As an Exchange professional, you need to know how to create and remove a mailbox database, how to mount and dismount it, how to modify its size limit, and how to change the database path. You need to know how to configure database properties and how to set the maintenance schedule.

To create and configure a mailbox database, you require the Organization Management, Server Management, or Storage Management role. The following high-level procedure creates a mailbox database in the EMC:

You can create a mailbox database in EMS using the New-MailboxDatabase cmdlet. For example, the following command creates the mailbox database MyMailboxDatabase and specifies the .edb database file path C:\MyDatabaseFiles\MyMailboxDatabase.edb and the log folder path D:\MyDatabaseFiles\LogFolder:

New-MailboxDatabase -Name "MyMailboxDatabase" -Server VAN-EX1 -EdbFilePath
C:\MyDatabaseFiles\MyMailboxDatabase.edb -LogFolderPath D:\MyDatabaseFiles\
LogFolder

Note:

NEW-MAILBOXDATABASE

For more information about the New-MailboxDatabase cmdlet, including its associated command syntax, see http://technet.microsoft.com/en-us/library/aa997976.aspx.

2.1. Mounting a Database

The procedure to mount a database is straightforward. In the EMC, click Mailbox under Organization Configuration and in the Result pane select the server on which the database is located. In the Work pane, select the mailbox database that you want to mount and then click Mount in the Action pane. If you create a new database using the EMC, you can choose to select the Mount This Database check box, in which case the newly created database is automatically mounted.

If the mailbox database is already mounted and you want to dismount it, the procedure is the same except you click Dismount in the Action pane. A warning appears asking if you want to dismount the database, and you click Yes.

In the EMS, you use the Mount-Database cmdlet. For example, the following command mounts the mailbox database MyMailboxDatabase. If you use the New-MailboxDatabase cmdlet in the EMS to create a mailbox database, you need to mount it after it is created.

Mount-Database -Identity MyMailboxDatabase.

The following command dismounts the mailbox database MyMailboxDatabase:

Dismount-Database -Identity MyMailboxDatabase

Note:

MOUNTING AND DISMOUNTING A DATABASE

The Microsoft Exchange Information Store (MSExchangeIS) service needs to be running before you can mount or dismount a database.

2.2. Removing a Database

The procedure for removing a mailbox database is also straightforward. In the EMC, you click Mailbox under Organization Configuration, click the mailbox database you want to remove in the Work pane, and then click Remove in the Action pane. A warning appears asking if you are sure you want to remove the mailbox database, and you click Yes.

To remove a mailbox database using the EMS, you use the Remove-MailboxDatabase cmdlet. For example, the following command removes the mailbox database MyMailboxDatabase:

Remove-MailboxDatabase -Identity MyMailboxDatabase

You are prompted to confirm that you want to perform the action. Type Y.

Note:

Bear in mind that the New-MailboxDatabase cmdlet syntax requires the Name parameter, while the syntax of cmdlets to configure, mount, dismount, or remove a database (for example, Remove-MailboxDatabase) requires the Identity parameter.

Whether you use the EMC or the EMS to remove a mailbox database, the procedure does not remove the database (.edb) file. In both cases, you are given the location of the file, and you can remove it manually. If you use the EMC, you need to click OK to close the dialog box that gives you this information.

Note:

REMOVE-MAILBOXDATABASE

For more information about the Remove-MailboxDatabase cmdlet, see http://technet.microsoft.com/en-us/library/aa997931.aspx.

2.3. Configuring the Database Size Limit

The Limits tab of the Mailbox Database Properties dialog box, shown in Figure 2-4 earlier in this lesson, lets you specify the limits at which warning messages are sent, Send is prohibited, and Send and Receive are prohibited. It does not, however, let you specify the size limit for the database. To do this, you need to configure the registry of the Exchange Server 2010 server that hosts the database.

The default database size limit for Exchange 2010 Standard Edition is 50 GB. There is no default database size limit for Exchange 2010 Enterprise Edition. The Exchange store periodically checks database size limits and dismounts a database if its size limit is reached. You can modify the database size limit by adding or changing a value in the registry on the server that hosts the database. This change will be propagated to all servers that hold a copy of the database.

To specify the size limit for a mailbox database, you first need to know the global unique identifier (GUID) of the database. You can obtain this by entering a command with the following syntax in EMS:

Get-MailboxDatabase -Identity "<server name>\<database name>" | Format-Table Name,GUID

					  

You then use the Registry Editor (regedit.exe) to locate the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\<server name>
\Private-<database GUID>

					  

If the Database Size Limit in GB DWORD exists for the subkey, change its value to the desired size in gigabytes. If the DWORD does not exist, create it and set its value to the desired size in gigabytes.

Warning:

Ensure that size limit changes do not affect your Service Level Agreements (SLAs). If you increase the size limits of your databases, this might lead to longer backup and restore times. Take care to ensure that such changes do not contravene your SLAs.

2.4. Changing the Path to the Mailbox Database

You can use both the EMC and the EMS to change the mailbox database path. Note that if you want to move a database path, the database is automatically dismounted (if necessary) so that it is inaccessible to users. If the database was previously mounted, it is automatically remounted when the move is complete. If the database was not mounted before the path is moved, it is not automatically remounted on completion.

The high-level procedure to use the EMC is as follows:

Move-DatabasePath -Identity MyMailboxDatabase -EdbFilePath C:\DifferentFolder\
MyMailboxDatabase

					  

If you know the GUID of the mailbox database, you can use this instead of the database name in the Identity parameter.

Note:

MOVE-DATABASEPATH

For more information about the Move-DatabasePath cmdlet, including its associated command syntax, see http://technet.microsoft.com/en-us/library/bb124742.aspx.

2.5. Configuring Mailbox Database Properties

Earlier in this lesson, we saw that the Mailbox Database Properties dialog box offers four tabs that let you view the general properties of the mailbox database, let you set a maintenance schedule and enable circular logging, let you configure warning and prohibit limits and how long deleted items are retained, and let you view and select the default public folder database and the offline address book (OAB) for the mailbox. You can also use the Set-MailboxDatabase cmdlet in EMS to configure mailbox database properties.

For example, the following command configures a deleted item retention time of 14 days for the mailbox database MyMailboxDatabase:

Set-MailboxDatabase -Identity "MyMailboxDatabase" -DeletedItemRetention 14.00:00:00

					  

Note that you can set a deleted item retention time for an individual mailbox. If you do so, this overrides the deleted item retention time set on the mailbox database that contains that particular mailbox.

Exchange database maintenance includes removing items that have passed their retention period, removing unused indexes, and other cleanup tasks. Optionally, it can also include online defragmentation, although you can configure this to occur continuously. The following command schedules maintenance to run from Sunday of each week at 10:30 PM until Monday at 1:30 AM:

Set-MailboxDatabase -Identity "MyMailboxDatabase" -MaintenanceSchedule "Sun.10:30 PM-
Mon.1:30 AM"

					  

Set-MailboxDatabase -Identity "MyMailboxDatabase" -MaintenanceSchedule 6.21:00-6.23:15

					  

Note:

SET-MAILBOXDATABASE

The Set-MailboxDatabase cmdlet is very versatile and supports a large number of parameters. For more information about this cmdlet, including its associated command syntax, see http://technet.microsoft.com/en-us/library/bb123971.aspx.