HP BA322 90087 - Manual (Page 92)

SYS$SPECIFIC directory. When the system (or each system in a cluster) is rebooted after the
upgrade, AUTOGEN runs. If a recent AGEN$FEEDBACK.DAT file is available, it is used. The
data in this file helps AUTOGEN set system parameters for your specific applications and
workload.
NOTE: If you do not have a current AGEN$FEEDBACK.DAT file, AUTOGEN might calculate
system parameters that do not reflect your system's requirements. In that case, multiple cycles
of running AUTOGEN and rebooting might be necessary before all layered products can be
started. In some cases, successful startup can require additional entries in MODPARAMS.DAT.
This should not be necessary if a current AGEN$FEEDBACK.DAT file is available.
If you do not have the AGEN$FEEDBACK.DAT file on your system, HP recommends that you
create a current AGEN$FEEDBACK.DAT file during a time when your system is running under
a typical workload. To ensure the greatest data reliability, the system should be running for more
than 24 hours but less than 30 days. Enter the following command:
$ RUN SYS$SYSTEM:AGEN$FEEDBACK.EXE
This runs very quickly and should not affect the performance of your system while it executes.
You can also specify the SAVE_FEEDBACK option when you execute the
SYS$SYSTEM:SHUTDOWN.COM procedure; however, the data captured might not fully reflect
the typical workload on your system.
IMPORTANT: If you start AUTOGEN without specifying the execution-mode parameter
(FEEDBACK, NOFEEDBACK, or CHECK_FEEDBACK), AUTOGEN uses the feedback information
in its calculations. However, if the feedback information reflects system up time of less than 24
hours, or if the feedback information is more than 30 days old, AUTOGEN includes warnings
in the AGEN$PARAMS.REPORT file to alert you to potential problems with the feedback data.
If you wrongly assume the feedback is valid, the parameter settings might vary significantly
from your expectations.
If you specify FEEDBACK (or NOFEEDBACK), AUTOGEN uses (or does not use) the feedback
regardless of the data’s reliability. AUTOGEN proceeds through the SETPARAMS phase (if you
specified SETPARAMS, SHUTDOWN, or REBOOT as the end phase) and sets system parameters
to the values it computed.
If you specify CHECK_FEEDBACK, AUTOGEN checks the validity of the feedback data. If
AUTOGEN determines the feedback is suspect, then AUTOGEN ignores the feedback when
computing parameter values. It stops at the TESTFILES phase and issues a warning in the report
that parameters have not been changed. You must read the report and decide whether the
calculated values are acceptable. You can either use them (by running the AUTOGEN
SETPARAMS phase) or rerun AUTOGEN with valid feedback data.
4.9 Shadowing Environment
Because you cannot upgrade the operating system on a shadowed system disk (the upgrade will
fail), you need to disable shadowing of the system disk and perform other operations before you
can upgrade the operating system.
There are several methods for creating a nonshadowed target disk. This section describes how
to change one of your existing shadowed system disks in a multiple-member shadow set to a
nonshadowed disk that you can use as your target disk for the upgrade.
If you have a larger configuration with disks that you can access physically, you might want to
use a copy of the system disk as your target disk. HP Volume Shadowing for OpenVMS describes
two methods you can use to create this copy (using volume shadowing commands or BACKUP
commands) and how to disable volume shadowing.
92 Before Upgrading the OpenVMS Operating System