Before we start talking about how to perform a manual seeding of a database copy, it would
be a good idea to define the term seeding in terms of LCR. Seeding is the process whereby
a database is added to a storage group copy. This can be a blank database or a copy of the
database the storage group uses as the production database.
When you enable LCR on a storage group using the EMC or via the EMS using the Enable-DatabaseCopy and Enable-StorageGroupCopy CMDlets, seeding normally takes place automatically. If it happens automatically, why should we even care about it, then? The answer is that there are a few situations in which manually seeding is required.
- The first is after you have performed an offline defragmentation of the production database belonging to the storage group for which you have enabled LCR.
- The second is if or when Exchange detects a corrupt log file, which the Microsoft Exchange Replication Service cannot replay into the database copy.
- The third is after a page scrubbing of a database on the active node in a Cluster Continuous Replication (CCR) setup occurs, and you then want to propagate these changes to the passive node in the CCR setup.
Yes, you're right, the last one isn't really related to LCR but only continuous replication in clustered environments, where CCR is used. We'll talk much more about CCR later in this chapter.
Seeding a database copy manually can be done using the Update-StorageGroupCopy
CMDlet in the EMS. Before doing so, you must suspend LCR for the respective storage
group and then remove any .log, .chk, .jrs, and .edb files from the passive storage group's
database copy, log files, and system files paths. To seed the database copy for the First Storage
Group, you use the Update-StorageGroupCopy CMDlet and type Update-
StorageGroupCopy-Identity: "First Storage Group."
Running this command will create a temporary temp-seeding folder, and after a little while the seeding will take place, as shown in Figure 8.19.
Figure 8.19 Seeding a mailbox database copy. (Click on image for enlarged view.)
When seeding has taken place, the Microsoft Exchange Replication Service will start to
replicate any .log, .chk, and .jrs files to the folder paths. When it's finished, you can resume
LCR for the storage group, and you're back in business.
If you don't want to delete any .log, .chk, .jrs, and .edb files manually before running the
Update-StorageGroupCopy CMDlet, you can tell the CMDlet to do it for you using the
DeleteExistingFiles parameter. This method requires that you confirm the deletion of these
files, as shown in Figure 8.20. The method you use is up to you, since they do the same
thing.
Figure 8.20 Specifying that the StorageGroupCopy CMDlet delete any
existing files. (Click on image for enlarged view.)
In addition, you can use the ManualResume parameter if you don't want replication to
occur automatically on the storage group copy.
Another method available for seeding a database copy is to dismount the database in the
EMC, suspend LCR for the storage group containing the database, and then copy the .edb
file to the LCR copy folder using Windows Explorer. When the file has been copied, you
then mount the database again using the EMC and resume LCR. Bear in mind that if you
choose this method, your end users will be disconnected until the database is mounted. So
unless there's a specific reason that you would use this method, we recommend that you use
the StorageGroupCopy CMDlet.
Managing Local Continuous Replication in Exchange 2007
Home: Introduction
Part 1: Exchange 2007 Local Continuous Replication overview
Part 2: Enabling Local Continuous Replication on a storage group
Part 3: Viewing the status for a Local Continuous Replication copy
Part 4: Switching to the LCR copy for database disaster recovery
Part 5: Suspending and resuming LCR for an Exchange 2007 storage group
Part 6: Manually adding an Exchange 2007 database to a storage group copy
Part 7: Use Exchange Eseutil for a passive storage group copy integrity check
Part 8: Disabling LCR on an Exchange 2007 storage group
Part 9: Adding Local Continuous Replication performance objects and counters
Part 10: Exchange 2007 LCR administration summarized
