The HP-UX Parallel rc Framework

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An Introduction

Executive Summary .............................................................................................................................. 2

Intended Audience............................................................................................................................... 2

Terms and Definitions........................................................................................................................... 2

The Working of the Traditional rc Script Sequencer ................................................................................. 2

Installing and Enabling the Parallel rc Execution Infrastructure ................................................................... 3

The Working of the Parallel rc Framework .............................................................................................. 3

Dependencies.................................................................................................................................. 3

Compatibility................................................................................................................................... 4

Partially Specified Dependencies ....................................................................................................... 5

Debugging Bottlenecks to Parallelism ..................................................................................................... 5

System Configuration Guidelines ........................................................................................................... 6

Adding rc Scripts into the Parallel rc Framework...................................................................................... 7

For HP-UX11iv3: .............................................................................................................................. 7

For the next Enterprise HP-UX release: ................................................................................................ 7

Appendix A: Performance improvement guidelines for individual RC scripts................................................ 7

For more information............................................................................................................................ 9

Summary of content (9 pages)

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The HP-UX Parallel rc Framework An Introduction Executive Summary .............................................................................................................................. 2 Intended Audience............................................................................................................................... 2 Terms and Definitions ...........................................................................................................................
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Executive Summary On HP-UX, traditionally, the rc sequencer is used to execute start or kill scripts when the system enters into a new run level. The rc sequencer executes the scripts sequentially. It waits for a script to complete before executing the next script in the sequence. This works well when the scripts are simple and the number of scripts is small. The increase in complexity and number of scripts has lead to longer waiting time for the system to switch between run levels.
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start script is represented by the name S019setboot. Within a run level, both start and kill scripts are executed in ascending alphabetical order. The entire name of the script is used for ordering. During the transition from a lower (existing) run level to a higher (destination) run level, all start scripts in the intermediate run levels in ascending order are executed culminating in the execution of the start scripts in the destination run level.
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services or resources set up by script a. Dependencies can be queried, added or changed using the rcutil(1M) command. The options to query dependencies are divided into two parts: 1. The -d and -o options are used to query the dependencies between rc scripts. 2. The –a, -b and –p options are used to query the order of execution of rc scripts installed on the system. When a start script dependency is specified, the given script will execute only after the scripts it depends on are executed.
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2. For kill scripts, all other kill scripts within the run level whose names are alphabetically greater than the given script are guaranteed to run after the given script. These steps ensure that the Parallel rc Execution Infrastructure honors the implicit dependencies for scripts that have not been enhanced to use the Parallel rc Framework. Partially Specified Dependencies HP recommends that you either specify all or no dependencies for any given script in the Parallel rc Framework.
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For example - if the script under investigation is /sbin/rc2.d/S730cron, then run the following command: rcutil –p S730cron Manually inspect the scripts run in parallel with the given script. If it appears that the given script depends on some of these scripts, or if some of these scripts share a resource with the given script, then place a dependency from the given script on these other scripts.
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Adding rc Scripts into the Parallel rc Framework ISV or customer products which have RC scripts can benefit from the Parallel rc Framework. The following needs to be done: For HP-UX11iv3: 1. An install time dependency for the product which needs to be added to Parallel rc Framework, has to be placed on the PARLL-RC_ENH product present in the RCEnhancement bundle. 2.
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Some startup and shutdown scripts source the system configuration variables by executing /etc/rc.config, which may not be needed since /sbin/rc would run them before invoking the startup and shutdown scripts. For example: # source the system configuration variables if [ -f /etc/rc.config ] ; then . /etc/rc.config else echo "ERROR: /etc/rc.config defaults file MISSING" fi This sourcing is done to ensure that the required system configuration variables are set.
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For more information http://www.hp.com/go/hpux-core-docs rc(1M) manual, init(1M) manual, top(1)manual, iostat(1) manual, vmstat(1)manual, sar(1M) manual www.hp.com/go/caliper © Copyright 2010 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services.