With Microsoft is getting ready to release Version 2 of Data Protection Manager (DPM), its disk-to-disk-to-tape backup solution, it might be a good time to look to re-evaluate the original version of Data Protection Manager to see where Microsoft is going with this product.
The idea behind Data Protection Manager is that data is backed up throughout the day, rather than once each night.
Inside many organizations, tape backups are no longer ideal backup solutions. First of all, the amount of data being backed up is growing exponentially. Unless you've purged a major amount of data, you'll be backing up more data tonight than you did last night, and more tomorrow night than tonight.
Many companies deal with this by implementing incremental or differential backups. The problem is that if a file is open, it usually cannot be backed up. If a company is doing business 24 hours a day, then closing files for a few hours each night so that the backup can run would be disruptive to its business.
Problems with traditional backups
Another problem with traditional backups is that they usually occur only once per night. If someone in your organization creates an important file at 9 a.m., and the file is accidentally deleted at 4 p.m., there'd be no way of recovering the file with a traditional backup system because it had not been backed up yet.
Here's another flaw with traditional backup techniques. Suppose that the file had been backed up and was accidentally deleted at 4 p.m. the next day. It would seemingly be easy to recover the deleted file. The problem is that by now, most organizations would have already shipped the previous night's backup tape off-site. Therefore, it would take time to retrieve the backup tape, and the network administrator would have to spend time manually restoring the file from the tape.
These are the types of problems that Microsoft tackled when it created the first version of Data Protection Manager (DPM), its disk-to-disk-to-tape backup solution. The idea behind the product is that data is backed up throughout the day, rather than once each night.
How Data Protection Manager works
DPM takes snapshots of the data, then stores those snapshots on a dedicated hard disk. Because of the way that the snapshots are made, it doesn't matter if the files being backed up are open or closed. This means that the backup window is no longer an issue. In many organizations (including mine), backups are run hourly. Under no circumstances should users ever lose more than an hour's worth of work.
If a restore operation does become necessary, there is no need to hunt for a backup tape. The DPM server stores many days worth of backups on its hard drive. The actual retention time varies with disk capacity and the number of backups being performed daily, but in my organization, 26 days worth of backups are retained on the DPM server. Not only do you not have to locate a backup tape, but the software can also be configured to allow users to restore files themselves.
As an added measure of protection, the DPM server is usually a backup to tape. This way, DPM server can act as the organization's primary backup. But if a catastrophe were to destroy the data center, there is still a tape that can be restored.
In many ways DPM is far superior to traditional backups, but it does have its shortcomings. Microsoft has addressed many of these shortcomings in the second version of DPM, which is being beta tested and is slated for release later this year.
Enhancements in Version 2 include the capability of performing synchronizations every 15 minutes (as opposed to hourly), thereby cutting potential data loss by 75%.
Microsoft has also tackled the issue of disk space consumption in version 2. Imagine the disk space it would normally take to keep almost a month's worth of the backups on hand. The first version of DPM went to great lengths to conserve disk space. When a file was modified, DPM would back up only the bytes that had changed -- not the entire file. This in itself conserved a tremendous amount of disk space, but Microsoft took it a step further by also offering single-instance storage.
DPM version 2 continues to use these features but adds a compression technology to remove redundancy from files. According to Microsoft, the amount of disk space required for backups has been decreased by up to 90%.
Biggest improvement in Data Protection Manager
Probably the most significant improvement to DPM is in applications support. The original version of the product was great for backing up file servers, but it was virtually powerless to back up database servers. Version 2 has been designed to offer continuous protection to servers running Exchange Server 2003 or 2007, SQL Server and SharePoint Portal Server. Version 2 also offers full support of clustered and 64-bit deployments of these applications.
Another shortcoming of the first version was that its protection of a server's system volume was limited. It was possible to back up files on the system volume, but DPM would not allow a system state restore (although individual files could be restored).
DPM Version 2 supports bare metal restores for servers. In the event of a catastrophic server failure, even a bare metal restore to different hardware can be performed.
Note: There is going to be some administrative work involved in deploying DPM Version 2, because agents used with the first version will not work with the new version. Existing agents will have to be removed before the new agents can be installed.
About the author: Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server, Exchange Server and IIS. He has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. He writes regularly for SearchWinComputing.com and other TechTarget sites.
More information on this topic:
