I've used system center data protection Manager (DPM) since the 2007 beta, primarily for sharepoint and sql backups & Exchange Backups. At a customer they have one DPM server which backs up to disk and additionally to a hp MSL2024 Tape Library for long term protection. The runs windows server 2008 r2 with DPM 2010 since its release.
After updating de DPM Server with SP1 for Windows 2008 r2 en updated the drivers. I had some issues with DPM. What I found was that although DPM installed correctly it couldn't see all the tape drives in the VTL. All the tape drives were visible in Device Manager and none were showing errors. I use the RECOMMENDED * HP StorageWorks Tape Drivers for Windows
In the DPM console under Management -> Libraries, the library was listed, but Total Drives was 0, rather than the expected 2. The DPM console showed the following error:
I followed the instructions to remap the drives here: http://technet.microsoft.com/en-us/library/bb795782.aspx. The DPMLA.xml file produced by the tool was correct, showing the correct SCSI IDs, serial numbers etc. but DPM still couldn't see the drives.
I found the solution to the problem on the DPM forum here: http://social.technet.microsoft.com/Forums/en-US/dpmtapebackuprecovery/thread/1d599443-7bf6-437a-bf12-52847fa7c8e5/ What I did is update the tape drive driver to the Inbox LTO driver as described on the forum and below:
1) Open device manager
2) Locate the tape drive
3) Right-click and look at the properties.
3) Under the DRIVER tab, select UPDATE DRIVER
a) Select the Install from list or specific location (Advanvced) – next.
b) Select Don't search. I will choose the driver to install. – next.
c) Uncheck the Show comtabile hardware checkbox.
d) Highlight LTO under the manufacturer.
e) Highlight the LTO tape drive under model – then next.
f) This should install the microsoft ltotape.sys driver.
4) Rescan the tape library in the DPM console – try to take another backup.
After following the above steps, all the two tape drives were visible in the DPM console.