Backup and Recovery with Server 2008
Logically, if
Server 2008 doesn’t support a streaming online backup of Exchange
databases, you have to pursue a third-party solution. The support is
still in place internally for streaming backups (although remote
streaming backup support has been removed on Server 2008). What you are
looking for in a backup solution is one that supports both streaming and
VSS solutions.
You might look into a
third-party solution that can perform the streaming backup (or VSS
backup), but remember that you cannot make a remote streaming backup
regardless of the solution you employ because a remote backup with
Exchange 2007 SP1 and Server 2008 is not supported.
Microsoft offers a solution called Microsoft System Center Data Protection Manager (DPM) 2007, shown in Figure3.
The Microsoft System Center product line is designed to assist
administrators with managing their server infrastructures. Data
protection is a key aspect of administrative management and so the DPM
is designed to assist with Exchange, SQL, SharePoint Services, and even
file shares from 2003/2008 Windows servers.
Note
Both
Server 2003 and 2008 have VSS capabilities. With Server 2003, the
NTBackup program cannot perform VSS backups, so you require a
third-party solution to take advantage of this solution. Server 2008
Windows Server Backup does include this feature; however, as already
mentioned, not for Exchange. In both cases, you can install Data
Protection Manager. This provides VSS support for your Server 2003
system and provides VSS and standard backup support for both Server 2003
and Server 2008.
We can say much regarding
the capabilities of DPM. A few items that stand out are that it has the
capability to perform more than a storage group or database backup and
restoration. You can also restore an individual mailbox or Public
Folder, which is a time saver and eliminates an administrative headache.
Keep in mind though that third-party solutions offer that capability
too, and DPM, although not a third-party solution, is still an external
solution. It’s a solution that doesn’t come with the operating system,
costs you money, and requires time to learn, similar to a third-party
backup solution. It simply comes from Microsoft and that might appeal to
you in that it should function well with other Microsoft products, in
this case Exchange 2007 with all of its features.
One of the
features supported by DPM is the high availability options and creating
copies of your data from the passive nodes of your clusters. You have
the capability to go from disk to disk and then to tape for your offline
solution.
Finally, DPM uses VSS shadow copies (a feature not supported by NTBackup) to create quick block-level difference backups.
What are Volume Shadow Copies?
Volume Snapshot
Service, or Volume Shadow Copies (typically expressed as VSS) is a
feature that we might be more familiar with functionally than
technologically. The reason we say this is because it isn’t a new
concept; in fact, we have had aspects of VSS in our Windows operating
system since Windows XP SP1. Server 2003, 2008, and Vista all have
aspects of VSS implemented. If you have used the System Restore or
Previous Versions features, you have used a form of VSS.
However, the question is: What is VSS?
Simply put, your system
takes a point-in-time snapshot of your data. It first looks at what you
have from the first snapshot and then, rather than performing complete
backups going forward, looks for changes to data and only backs up the
changes.
Here is the overall process of an Exchange backup using VSS:
The
VSS requester (your backup software, which is going to have to be a
third-party solution for Exchange with either Server 2003 or 2008) is
told to begin the VSS backup or create the shadow copy.
The
VSS writer (the Exchange database information store) freezes the
databases to ensure you have no new writes to the databases. Note that
for this reason, with continuous replication solutions and clusters, it
is recommended you use the passive copy of the database because you have
less of a chance that the procedure will fail due to writes coming in.
The VSS provider (the hardware and software that create the snapshot) creates the snapshot.
The VSS writer is told when the copy is complete and will allow writes to the database again.
The VSS requester (your backup software) lets you know the copy was complete.
There are varieties of ways
the technology is advancing on all fronts (software and hardware) to
improve the way these copies work. However, overall they are faster and
take up less disk space then a traditional backup would.
