IBM TS2340 User Guide - Page 99

Notes, command and the option 53

Page 99 highlights

HP-UX Device Driver (ATDD) Control Path Failover Support for Tape Libraries Notes: 1. The library control path failover feature code must be installed prior to enabling the path failover support in the HP-UX ATDD device driver. Refer to "Automatic Failover" on page 12 for what feature code may be required for your machine type. 2. It is a requirement that applications must open the primary path for CPF Configuring and Unconfiguring Path Failover Support Path failover support is enabled automatically when the device driver is installed; however, the driver provides a kernel parameter you can use to enable library control path failover. To enable the failover support in the ATDD driver, perform the following steps after installing the driver: v In HP-UX 11.0, 11i v1 and v2: 1. Set the alternate_pathing parameter: # /opt/atdd/bin/atdd_failover -a 1 2. Reconfigure CPF for the devices: # /opt/atdd/bin/atdd_claim v In HP-UX 11i v3: Run kctune to enable the kernel tunable of atdd_alternate_pathing. ATDD handles the CPF in the next open. # kctune atdd_alternate_pathing=1 * The automatic 'backup' configuration has been updated. * The requested changes have been applied to the currently running configuration. Tunable Value Expression Changes atdd_alternate_pathing (before) 0 0 Immed (now) 1 1 You can check if the driver has recognized multiple control paths for your library by running: #ioscan -funC autoch If you see .altpath next to one of the special files in HP-UX 11.0, 11i v1 and v2, then you have successfully enabled the control path failover feature for your library. In HP-UX 11i v3, use the # ioscan -m dsf command and the option 53 of "Display Path" in tapeutil to verify that the multiple path is configured by the system and ATDD. After the path failover support is enabled, it remains set until atdd_claim is run with the alternate_pathing driver parameter set to OFF . The path failover setting is retained even if the system is rebooted. If you want to turn off the control path failover feature in the ATDD driver, perform the following steps: v In HP-UX 11.0, 11i v1 and v2: 1. Clear the alternate_pathing parameter: # /opt/atdd/bin/atdd_failover -a 0 2. Reconfigure CPF for the devices: # /opt/atdd/bin/atdd_claim v In HP-UX 11i v3: Run kctune to disable the kernel tunable of atdd_alternate_pathing. ATDD manages the CPF in the next open. Chapter 4. HP-UX Tape and Medium Changer Device Driver 81

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Control Path Failover Support for Tape Libraries
Notes:
1.
The library control path failover feature code must be installed prior to
enabling the path failover support in the HP-UX ATDD device driver. Refer to
“Automatic Failover” on page 12 for what feature code may be required for
your machine type.
2.
It is a requirement that applications must open the primary path for CPF
Configuring and Unconfiguring Path Failover Support
Path failover support is enabled automatically when the device driver is installed;
however, the driver provides a kernel parameter you can use to enable library
control path failover. To enable the failover support in theATDD driver, perform
the following steps after installing the driver:
v
In HP-UX 11.0, 11i v1 and v2:
1.
Set the alternate_pathing parameter:
#
/opt/atdd/bin/atdd_failover -a 1
2.
Reconfigure CPF for the devices:
#
/opt/atdd/bin/atdd_claim
v
In HP-UX 11i v3:
Run
kctune
to enable the kernel tunable of atdd_alternate_pathing. ATDD
handles the CPF in the next open.
# kctune atdd_alternate_pathing=1
* The automatic 'backup' configuration has been updated.
* The requested changes have been applied to the currently
running configuration.
Tunable
Value
Expression
Changes
atdd_alternate_pathing
(before)
0
0
Immed
(now)
1
1
You can check if the driver has recognized multiple control paths for your
library by running:
#ioscan -funC autoch
If you see
.altpath
next to one of the special files in HP-UX 11.0, 11i v1 and v2,
then you have successfully enabled the control path failover feature for your
library. In HP-UX 11i v3, use the
# ioscan -m dsf
command and the option 53 of
“Display Path” in tapeutil to verify that the multiple path is configured by the
system and ATDD.
After the path failover support is enabled, it remains set until atdd_claim is run
with the alternate_pathing driver parameter set to OFF . The path failover setting
is retained even if the system is rebooted. If you want to turn off the control path
failover feature in the ATDD driver, perform the following steps:
v
In HP-UX 11.0, 11i v1 and v2:
1.
Clear the alternate_pathing parameter:
#
/opt/atdd/bin/atdd_failover -a 0
2.
Reconfigure CPF for the devices:
#
/opt/atdd/bin/atdd_claim
v
In HP-UX 11i v3:
Run
kctune
to disable the kernel tunable of atdd_alternate_pathing. ATDD
manages the CPF in the next open.
HP-UX Device Driver (ATDD)
Chapter 4. HP-UX Tape and Medium Changer Device Driver
81