My Understanding of DPM and How It Relates to Traditional Backups

I don't have any projects in my new Jr Admin role but my new boss gave me access to and documentation for our Data Protection Manager, or DPM server. I don't necessarily have to memorize how to do everything with it: Just get a decent grasp for how it works and the rest will come. Before jumping head first into DPM, I wanted to refresh on traditional backups and how they work.


There are 3 different types of backups: Full, Incremental, and Differential;

• Full Backup
• Exactly as it sounds; It's a backup of all the things. When you have multiple full-backups, files from each can be moved, copied or recovered independently. The downside is that multiple full backups take up a lot of space. 
• Differential Backup
• A Differential backup backs up data that has changed since the last full backup. Differential backups are great when it comes time to restore files because each one records the changes since the last full backup. If you needed to restore a file, you'd only need the file from the latest full backup and the latest differential.
• Incremental Backup
• An Incremental backup backs up data that has changed since the last backup (Full or Differential.) If you needed to restore a file, you'd need the file from the latest full backup and then apply each incremental backup up to the latest. 

For example's sake, let's say you take a Full backup every Monday morning. On Tuesday morning, a differential backup would be backing up the files that have changed since Monday morning. On Wednesday morning, an incremental backup would be backing up the files that've changed since Tuesday. A differential backup would be backing up files that've changed since Monday. See where this is going?

I spent a bit of time recently reading up on DPM. After about 5 solid hours of reading (and Googling), here's what I've found:

• There's a client and a server. The DPM Service runs on a server and the DPM Protection Agent is installed on client computers (could be either workstations and/or other servers)
• Computers you want to backup that have DPM Protection Agent installed are collectively referred to as Protected Computers. Likewise, shares, volumes and directories are collectively referred to as Protected Data.
• The DPM Protection Agent installs on computers with data you wish to back up with DPM. It does several things:
• It keeps track of changes made to data in a change journal. A change journal is made for each protected volume for that computer and is kept in a hidden file on that volume.
• It transfers the change journal from the protected computer to the DPM server so DPM can synchronize the replica (more on Synchronization later). 
• It allows the DPM server to browse shares, volumes and directories on the protected computer. 
• DPM saves Application Data and File Data differently. (More on that later. For now, it's important to note that DPM is smart enough to know whether it's backing up flat files (Word docs, text files, pictures, etc) or whether it's backing up Exchange mailbox data stores, SQL databases, etc.)
• DPM organizes into Protection Groups. Protection Groups are Protected Computers or volumes that share the same Protection Configuration. 
• Protection Configuration for a Protection Group consists of where the storage pool is (ie, where to backup the data), how often to synchronize the data, and when to create Recovery Points. You can also specify whether On-The-Wire compression or Daily Consistency Checks are enabled. 
• DPM creates a Replica of the data it's protecting and saves it to a storage pool (other disks, tape drive, SAN, etc) when a share or computer is added to a Protection Group. A replica is akin to a Full Backup. It's a complete copy of the data within the data source. 
• DPM creates Recovery Points, which allow users or administrators to recover previous versions of protected data. Recovery Points may also be referred to as Snapshots. They're a point-in-time copy of a replica stored in a storage pool. 8 Recovery Points can be created per day. Recovery points are akin to Differential backups.
• DPM performs Synchronization by transferring data changes from a data source to a DPM server and then applying the changes to the replica. This is similar to Incremental backups. There are 2 types of Synchronization that can be performed. 
• Incremental Synchronization - Exactly as described above. It simply checks to see what's changed on the data source and updates the replica accordingly. (This is often simply referred to as a sync or synchronization.)
• Synchronization with Consistency Check - This type of synchronization also does the same as an Incremental Synchronization but does a block-level check of the replica to make sure that all the data is consistent with the data from the data source and resolves inconsistencies if necessary. (This is often referred to as a Consistency Check rather than the title listed above.)
• Retention Range for protected data is how far back you can go to recover data. 

For best results, read that everyday for at least 5 days straight in order to allow all that new jargon you just learned to properly marinate in your brain.