IBM TS2340 User Guide - Page 201

Windows Device Driver Data Path Failover Support for Tape Drives To take advantage of Windows Data Path Failover (DPF) support, the appropriate feature code must be installed. Refer to "Automatic Failover" on page 12 for what feature code may be required for your machine type. Configuring and Unconfiguring Data Path Failover Support Data Path Failover support is enabled automatically when the device driver is installed. It may be disabled or reenabled for the entire set of attached drives or medium changers by modifying the registry. 1. Open the reg folder of the driver package. 2. Double click DisableDPF.reg or EnableDPF.reg. 3. Reboot the system. This is necessary for any registry modification to take effect. For LTO generation 3 or lower, for tape drives that require a data path license key on the host side to enable DPF, the device driver looks for a file called %system_root%:\IBM_DPF.txt for the key, where: %system_root% is the drive letter where Windows has been installed, typically C, (for example, C:\IBM_DPF.txt). The file should contain the key on a single line, with no spaces and no other text on the line. If multiple keys are required, place each key in the file on its own line. The driver looks for this file at initialization, and if the file contains a valid DPF license key, the DPF feature is enabled and any eligible devices have multi-path support. Note: For LTO generation 3 running the latest drive microcode, there is no longer a requirement to provide a DPF license key in IBM_DPF.txt. The microcode now handles the enablement of the DPF feature. Querying Primary and Alternate Path Configuration To check if the data path failover has been enabled in the device driver and display the primary and alternate paths you may use the tape diagnostic and utility tool. Note: Display the primary and alternate path configuration for any device using tape diagnostic and utility functions, refer to Chapter 10, "IBM Tape Diagnostic Tool (ITDT)," on page 259 or "Microsoft Windows System Utility Program (ntutil)" on page 406. Checking Disablement of Data Path Failover Setting If you have disabled the data path failover in device driver's setting by double clicking the DisableDPF.reg file and reboot your system, you may go into the registry by issuing the Windows regedit command to confirm that DPF has been disabled. Look for a line like the following if your system is Windows Server 2003 or Windows Server 2008: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ibmtp2kx] "FailoverDisabled"=dword:00000001 This indicates that DPF has been disabled in the driver. This setting only takes effect after your system is rebooted. Chapter 7. Windows Tape and Medium Changer Device Driver 183