DPM works by making shadow copies of your data. DPM is set up so it protects data on an hourly basis and makes shadow copies three times a day. It treats each shadow copy of a file as a separate version. Assuming that the DPM server has enough free disk space, DPM can retain up to 64 different versions of a file.
When DPM detects that a file has been modified, it does not treat those modifications as a separate file version (unless it happens to be time to make a new shadow copy). Instead, the modified bits are applied to the most recent shadow copy. This way, DPM can ensure that more than an hour's worth of data can never be lost, and that three separate versions of the file are saved each day (by default).
Why doesn't DPM just perform hourly shadow copies? First of all, to do so would require that DPM use more system resources. Secondly, making shadow copies three times a day allows about 21 days' worth of file versions to be retained. If shadow copies were made hourly, then less than three days' worth of file versions could be retained (because of the 64-version limit).
Still, one of DPM's greatest capabilities is its ability to retain multiple file versions. If you need to restore a file, the first thing to do is figure out is
Performing a basic recovery
A basic recovery involves recovering a file through the DPM 2006 Administrator Console. To do so:
- Open the DPM Administrator console and select the Recovery tab.
- You will see a list of the protected servers. Expand the listing for the server that contains the data that you want to recover. You will see two sub-containers: All Shares and All Volumes.
- Choose the appropriate container (depending on whether the server is protected at the share level or at the volume level) and expand it.
- You will see a listing of dates and times. In most cases, one of these date/time folders will correspond to the date/time range of the file you want to recover. If you do see a container bearing the appropriate date/time stamp, expand the container to reveal the protected files and folders.
- Right-click on the file or folder you want to recover and select the Recover command from the resulting shortcut menu.
Suppose a container with the desired date/time stamp does not exist. Does that mean that no files from the requested time period are available? No. DPM shows only the most recent replica containers.
If you need a file version older than the containers shown, go into any available container and find the file or folder you want to recover. Right-click on the file or folder and select the Show All Versions command from the shortcut menu. DPM will now display the All Versions dialog box. It may take a few minutes, but the dialog box will eventually be populated with a list of all available versions of the file or folder. Pick the version that you want, and click the Recover button.
Searching for data to recover
You can use DPM's built-in search engine to locate data for recovery. Suppose a user wanted you to recover a file named Tuesday.doc, but couldn't remember where the file was stored. If you didn't know the file's location, it could take forever to find the file by browsing the entire directory tree. Fortunately, instead click the Restore tab, then select the Search sub-tab. You'll now see a search engine that allows you to search the database for specific files.
Configuring end-user recovery
You can configure DPM it in a way that allows users to recover files by themselves instead of coming to you. First you will have to extend the Active Directory's schema. The process itself is no big deal, but I recommend backing up your domain controllers before extending the schema. If something were to go wrong during the process, your Active Directory could become corrupted.
To configure DPM to support end user recovery:
- Select the Recovery tab and click the Configure End User Recovery link.
- When the Options properties sheet opens, select the End User Recovery tab.
- Click the Configure Active Directory button.
- You will be prompted to enter a set of administrative credentials. When you do, you will see a message warning you that the Active Directory is about to be modified, and asking if you want to continue. Click Yes.
- Now relax for a few minutes while your Active Directory schema is extended.
Once the process is completed, select the Enable End User Recovery check box on the Options properties sheet's End User Recovery tab. The server is now ready to support end-user recovery. However, you must now install a DPM-aware shadow copy client on the user's workstation. You can download the Windows XP version of the client. Note: This version of the shadow copy client requires Windows XP to be running Service Pack 2.
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 SearchWinSystems.com and other TechTarget sites. This tip originally appeared on SearchWinSystems.com.
More information from SearchWinSystems.com
- Tip: Why DPM is replacing traditional disk-to-tape backups
- Topics: Backup
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This was first published in June 2006