8. The remaining tasks vary for each client environment. You must create storage pools by  using the device class that is configured for the VTL. Then, you must update the  management classes and backup/archive copy groups. After these steps are complete,  you can explore the advantages of the ProtecTIER product. 7. Define the device class in the IBM Spectrum Protect Server for the library (Example 13-8). Example 13-8 Device class configuration tsm: SERVER1>define devclass ptvtldevclass library=ptlibrary devtype=lto  estcapacity=100000M format=ultrium3 ANR2203I Device class PTCLASS defined. 13.2.15 Updating to a VTL library type You can update an existing small computer system interface (SCSI) library to a VTL library  type by running the following command:  update library <libname> LIBTYPE=VTL Updating the library to a VTL library type enables ProtecTIER to make more accurate  assumptions and skip unnecessary SCSI validations. Depending on the operating system,  you might run into limitations, such as 300 - 500 maximum drives. Setting the  LIBTYPE=VTL  also eliminates the restriction of defining only 120 tape drives when  you use IBM Spectrum Protect and the ProtecTIER product. This feature is available only with  Tivoli Storage Manager V6.3 or later. If you have a previous version of Tivoli Storage  Manager, you might want to review APAR IC66116  ( Large number of tape drives can cause  volume mounts to perform slowly) at the following website: http://www.ibm.com/support/docview.wss?uid=swg1IC66116 Updating the library:  The  UPDATE LIBRARY  function does not support mixed media, such  as drives with different device types or device generations in the same library (LTO2 and  LTO3). Also, this function requires that online paths be defined for servers and storage  agents to all drives in the library. If paths are missing or offline, the performance levels  degrade to the level of the SCSI library. Version 6.3 introduced the  PERFORM LIBACTION  command, which automatically defines the  library/path/drive structure in a single command. This action is helpful when you use the  ProtecTIER product because it usually contains many drives. When you run the  PERFORM  LIBACTION  command, complete the following steps: Use IBM Spectrum Protect to define and delete IBM Spectrum Protect libraries (VTL and  SCSI library types only) that contain many drives by running the following command:  PERFORM LIBACtion <library_name> device=xxx action=define 13.2.16 Defining and deleting IBM Spectrum Protect libraries with many drives 3. Define paths to the drives found in the library, respecting the virtual tape drive numbering. 2. Scan for all drives that belong to the library and define all drives that are found in  the library. 1. Create a path to the library. Chapter 13. IBM Spectrum Protect  199