In DPM 2007, you can assign a custom volume to a protection group member, in place of the DPM storage pool. A custom volume is a volume that is not in the DPM storage pool and is specified to store the replica and recovery points for a protection group member.
Although the DPM-managed storage pool is sufficient for most business needs, you might want a greater amount of control over storage for specific data sources. For example, you have critical data that you want to store using a high-performance logical unit number (LUN) on a storage area network.
Any volume that is attached to the DPM server can be selected as a custom volume in the Create New Protection Group Wizard, except the volume that contains the system and program files. To use custom volumes for a protection group member, two custom volumes must be available: one volume to store the replica and one volume to store the recovery points.
DPM cannot manage the space in custom volumes. If DPM alerts you that a custom replica volume or recovery point volume is running out of space, you must manually change the size of the custom volume by using Disk Management.
You cannot change the selection of storage pool or custom volume for a protection group member after the group is created. If you must change the storage location for a data source's replica or recovery points, you can do so only by removing the data source from protection and then adding it to a protection group as a new protection group member.