Here is the kb article from EMC website.
How can NetWorker be configured to backup a rawdevice?
How to backup a RAW device?
Fact  
NetWorker for UNIX/Linux 7.x.x
Resolution  
Create a directive using rawasm. Rawasm used to backup /dev entries (block andcharacter-special files) and their associated raw disk partitiondata. On some systems, /dev entries are actually symboliclinks to device specific names. Unlike other ASMs, this ASM followssymlinks, allowing the shorter /dev name to be configured.
- Open NMC.
- Go to the Configuration > Directives.
- Right Click > new.
- In the Name field enter Raw.
- In the directives field enter the directive in the following format:
 <
+rawasm: partition1
+rawasm: partition2
Click on Apply.
Close this window and go to the Clients menu    and select Client Setup. 
Select the client with the raw    devices. 
In the Saveset field specify:    
/dev/partition1
/dev/partition2
/dev/partition1
/dev/partition2
In the Directive field select Raw. 
Click on Apply.
Note:
Precautions when using rawasm to back up        UNIX raw partitions:            
One can specify the     rawasm         directive to back up raw disk partitions on    UNIX.  
However, if the raw partition contains data      managed by an active database management system (DBMS),      ensure that the partition is offline and the database manager      is shutdown. For greater flexibility when backing up      partitions that contain data managed by a DBMS, use a      NetWorker Module application.      
Similarly, if     rawasm         is used to save a partition containing a UNIX    file system, the file system must be unmounted or mounted    read-only to obtain a consistent backup.  
Note:         Do not specify the     rawasm         directive to backup or recover raw partitions    on Windows. See        Backing up raw      partitions on Windows on page 88         provides more information.  
Using rawasm to recover a UNIX raw        partition            
When recovering data,     rawasm         requires that the file system node for the    raw device exist prior to the recovery. This protects against    the recovery of a /dev entry and the overwriting of data on a    reconfigured disk. You can create the /dev entry, having it    refer to a different raw partition, and     enforce overwrite if needed. If you create    the /dev entry as a symbolic link, the data is recovered to the    target of the symbolic link.  
Recovery of a raw partition must occur on a    system configured with the same disk environment and same size    partitions as the system that performed the backup:  
- If the new partition is smaller than the original partition, the recovery will not complete successfully
- If the new partition is larger than the original partition the estimated size reported upon recovery is not accurate
Note: Only level FULL is supported      with rawasm, this is because the original NetWorker      traditional backup codes are designed for Filesystem      level Backup, and not Block Level backup.     
 
