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SYSTEM STARTUP
AND SHUTDOWN
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Introduction
This topic discusses how the systemenvironment should be managed.
It will explain the boot options suchas normal boot, maintenance boot,management services anddiagnostics.
And also it tells about startupprocess and shutdown process.
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Objectives
Describe the system startup process
Describe how to shutdown theprocess
Describe the contents of the/etc/inittab file
Manage the system environment
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Alog command
Description
The alog command reads standardinput, writes to standard output, and
copies the output into a fixed-size file. This works with log files that are
specified on the command line or with logsthat are defined in the alog configurationdatabase.
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Flags
-C
Changes the attributes for a specifiedLogType. Use the -C flag with the -f, -s,
and -w flags to change the File, Size, andVerbosity attributes for the specifiedLogType. The -t LogType flag is required.
-o
Lists the contents of LogFile. Writes thecontents of LogFile to standard output insequential order.
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-L
Lists the log types currentlydefined in the alog configurationdatabase.
-vWrites the current value of the
Verbosity attribute for LogType thatis defined in the alog configurationdatabase to standard output.
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Example
To list the contents of /tmp/sample.loglog file as,
alog -f /tmp/sample.log o
To record the current date and time in
a log file named sample. log,date | alog -f /tmp/sample.log
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Specified log Type
To display the current attributes of aspecified log type,
alog -L [ -t LogType ]
Example:
To change the name of the log file for thelog type sample to /var/sample.log in the
alog configuration database,alog -C -t sample -f /var/sample.log
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SYSTEM RESOURCE CONTROLLER
The system resource controller(SRC) provides a set of commands tomake it easier for the administrator
to control subsystems.Subsystem- A subsystem is a
program or set of related programsis designed to perform a function.This can be further divided intoSubservers.
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Subservers- subservers are similarto daemons.
Group- SRC was designed tominimize the need for userintervention since it provides controlof individual subsystem or group of
subsystems.Some subsystem have subservers.
For example the tcp/ip group
contains a subsystem, inetd, thatcontains several subservers forexample ftp and telnet.
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System Resource Controller Syntax
List SRC status1.The lssrc command is used to
show the status of SRC.
2. In following example we arechecking the status of spooler groupusing g.
# lssrc g spooler
3.To list the all processesa flag
is used.
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Start a subsystem
1.Startsrc command is usedto start the subsystems or groups.
2.In following example we arestarting the lpd subsystem.
# startsrc s lpd
3.-s and g options are usedto control the subsystems orsubsystem groups respectively.
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Stop a subsystem
1.Stopsrc is used to stop the
subsystems or groups.
2.lpd subsystem will be stoppedby following command.
# stopsrcs lpd
Kill command
Which processes are notcontrolled by SRC those can be stopped bykill command.
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Refresh a subsystem
1.Refresh command forcesthe subsystem to reread any of isconfiguration files.
2.Here we are refreshing thelpd daemon.
# refresh s lpd
3.lpd
The daemon thatcontrols the print server.
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System Shutdown
Gracefully stops all activity on thesystem and advises all log on users.
Warns users of a impendingshutdown.
The SMIT shutdown fastpath or theshutdown command is used to shutthe system down cleanly.
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Flags
-F Does the fast shutdown. -h Halts the operating system
completely.
-I Specifies interactive mode.
-k Avoids shutting down thesystem.
-m Brings the system down to
maintenance(singleuser)mode. -t Restarts the system on the date
specified by mmddHHMM.
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-r Restarts the system after being
shutdown with reboot command.
Example:
To shutdown the system tosingle user mode.
#cd /
#shutdown -m