Exchange 2007 : Enable Local Continuous Replication

Remember, to implement LCR you can only have one database per storage group. You want to make sure you certainly have sufficient disk space for your LCR copy. You can implement LCR in one of two ways—either during the creation of the storage group or afterward.

Enable LCR on an Existing Storage Group

If the storage group already exists, perform the following steps:

1.	Open the Exchange Management Console (EMC).
2.	From the Navigation Tree, expand the Server Configuration work center and click Mailbox.
3.	From the Results pane, choose the server that has the storage group on which you want to enable LCR.
4.	Select the storage group on which you want to enable LCR. (Note: If you select a storage group with more than one database, you will not even see the option to enable LCR.)
5.	From the Actions pane, select Enable Local Continuous Replication to open the wizard.
6.	On the Introduction screen, confirm the storage group name and database name, and click Next.
7.	On the Set Paths screen, you are shown the default paths, but these are generally to a local disk. You might allow this for testing purposes, but it defeats the purpose of LCR. You want to relocate those to a separate disk. Click the Browse buttons to relocate those paths to a new disk. Then click Next.
8.	You are shown the passive location of the database file (shown in Figure 1). Click Browse to alter this location as well. Then click Next. Figure 1. The Enable Storage Group Local Continuous Replication dialog.
9.	You are shown a configuration summary of both actions: making a copy of the database and making copies of the log and system files. Keep in mind that the database is copied once. The way it is kept up to date is through transaction logging and replaying into the database on the passive side. After you confirm your settings, click Enable.
10.	When complete, click Finish.

What happens next is a process called seeding, where your database is created in the passive disk and this is the creation of the starting point for your LCR version. After LCR is complete, you should notice a change in the icon next to your storage group. Some new options in the Actions pane for your storage group are to disable or suspend the LCR.

We need to revisit the process:

This completes the first part for creating a storage group that is LCR-enabled, but the next part is the database. When you create the database for the storage group, you need to browse for the location of the active database and for the location of the replicated database. When you are ready, click New and then Finish.

Verify LCR Is Functional

To see how your LCR performs, there is a tab in the properties of the storage group that shows you information regarding your LCR status. To view that information, perform the following:

Recover from Disk Failure

Unfortunately, there are times when your active disk might fail. With LCR you have to manually intervene, but you can recover your working environment quickly depending on how fast you are notified and how rapidly you can respond to the failed disk.

The process requires three actions:

• Dismount the database.

• Alter the pointer for the database to point at the passive copy. Note: If the disk itself is not harmed but the database has become corrupt, you don’t have the change the pointers; simply move the database over to the production location and remount. If the disk went bad, you need to alter the pointers.

Remount the database.

To perform these actions, do the following:

Keep in mind that LCR is no longer functioning on the storage group because you just disabled it by switching to your passive copy. You have to put in a new disk or simply configure LCR again to use the locations on different disks that you have prepared in your system.