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System Administration Guide, Volume 2

Using Commands to Change System Information

The table below shows man page references and descriptions for some commands that enable you to change general system information.

Table 27-2 Commands for Changing System Information

Command 

Enables You to Change a System's ... 

rdate(1M)

Date and time to match those of another system 

date(1)

Date and time to match your specifications 

Using these commands, you can set a system's date and time to synchronize with the date and time of another system, such as a server. Or you can change a system's date and time by specifying new information.

The message of the day (MOTD) facility, located in /etc/motd, enables you to send announcements or inquiries to all users of a system when they log in. Use this facility sparingly, and edit this file regularly to remove obsolete messages.

By editing the /etc/system file, you can:

Using Network Time Protocol (NTP) in Your Network

The Network Time Protocol (NTP) public domain software from the University of Delaware is included in the Solaris software starting with the Solaris 2.6 release.

NTP enables you to manage precise time and network clock synchronization in a network environment. The xntpd daemon sets and maintains the system time-of-day. The xntpd daemon is a complete implementation of the version 3 standard, as defined by RFC 1305.

The xntpd daemon reads the /etc/inet/ntp.conf file at system startup. See xntpd(1M) for information about configuration options.

Keep the following in mind when using NTP in your network:

How to Set Up an NTP Server

  1. Become superuser.

  2. Change to the /etc/inet directory.

  3. Copy the ntp.server file to the ntp.conf file.


    # cp ntp.server ntp.conf

  4. Change to the /etc/init.d directory.

  5. Start the xntpd daemon.


    # ./xntpd start

How to Set Up an NTP Client

  1. Become superuser.

  2. Change to the /etc/inet directory.

  3. Copy the ntp.client file to the ntp.conf file.


    # cp ntp.client ntp.conf

  4. Change to the /etc/init.d directory.

  5. Start the xntpd daemon.


    # ./xntpd start

How to Synchronize Date and Time From Another System

  1. Become superuser.

  2. To reset the date and time to synchronize with another system, use the rdate command. 


    # rdate another-system

    another-system

    Name of another system. 

  3. Verify that you have reset your system's date correctly by checking your system's date and time using the date command.

    The output should show a date and time that matches that of the other system.

Example--Synchronizing Date and Time From Another System

The following example shows how to use rdate to synchronize the date and time of one system with another. In this example, the system earth, running several hours behind, is reset to match the date and time of the server starbug. 


earth# date
Thu Sep 16 11:08:27 MDT 1999
earth# rdate starbug
Thu Sep 16 14:06:37 1999
earth# date
Thu Sep 16 14:06:40 MDT 1999

How to Set a System's Date and Time Manually

  1. Become superuser.

  2. Enter the new date and time. 


    # date mmddHHMM[[cc]yy]

    mm

    Month, using two digits. 

    dd

    Day of the month, using two digits. 

    HH

    Hour, using two digits and a 24-hour clock. 

    MM

    Minutes, using two digits. 

    cc

    Century, using two digits. 

    yy

    Year, using two digits. 

  3. Verify that you have reset your system's date correctly by checking your system's date and time using the date command with no options.

    The output should show a date and time that matches that of the other system.

Example--Setting a System's Date and Time Manually

The following example shows how to use date to manually set a system's date and time. 


# date
Thu Sep 16 14:00:00 MDT 1999
# date 0916141099
Thu Sep 16 14:10:00 MDT 1999

How to Set Up a Message of the Day

  1. Become superuser.

  2. Edit the /etc/motd file and add a message of your choice.

    Edit the text to include the message that will be displayed during the user login process, including spaces, Tabs, and Returns.

  3. Verify the changes by displaying the contents of the /etc/motd.


    $ cat /etc/motd
Welcome to the UNIX Universe. Have a nice day.

Example--Setting Up a Message of the Day

The default message of the day, provided when you install Solaris software, contains SunOS version information: 


$ cat /etc/motd
Sun Microsystems Inc.   SunOS 5.8       Generic  February 2000

The following example shows an edited /etc/motd file that provides information about system availability to each user who logs in. 


$ cat /etc/motd
The system will be down from 7:00 a.m to 2:00 p.m.on
Saturday, July 10, for upgrades and maintenance.
Do not try to access the system during those hours.
Thank you...

How to Set the Number of Processes per User

  1. Become superuser.

  2. Edit the /etc/system file and add the following line. 


    set maxuprc=value

    value

    Number of processes a user can run at once. 

  3. Verify the maxuprc value change.


    # grep maxuprc /etc/system
set maxuprc=100

  4. Reboot the system.

Example--Setting the Number of Processes per User

The following example shows the line you would add to the /etc/system file to allow users to run 100 processes each. 


set maxuprc=100

How to Increase Shared Memory Segments

  1. Become superuser.

  2. Edit the /etc/system file and add the following variables to increase shared memory segments. 


    set shmsys:shminfo_shmmax=value
set shmsys:shminfo_shmmin=value
set shmsys:shminfo_shmmni=value
set shmsys:shminfo_shmseg=value
set semsys:seminfo_semmap=value
set semsys:seminfo_semmni=value
set semsys:seminfo_semmns=value
set semsys:seminfo_semmsl=value
set semsys:seminfo_semmnu=value
set semsys:seminfo_semume=value

    shmsys:shminfo_shmmax

    Maximum shared memory segment size 

    shmsys:shminfo_shmmin

    Minimum shared memory segment size 

    shmsys:shminfo_shmmni

    Number of shared memory identifiers 

    shmsys:shminfo_shmseg

    Number of segments, per process 

    semsys:seminfo_semmap

    Number of entries in the semaphore map 

    semsys:seminfo_semmni

    Number of semaphore identifiers 

    semsys:seminfo_semmns

    Number of semaphores in the system 

    semsys:seminfo_semmsl

    Maximum number of semaphores, per ID 

    semsys:seminfo_semmnu

    Number of processes using the undo facility

    semsys:seminfo_semume

    Maximum number of undo structures per process

  3. Verify the shared memory value changes.


    # grep shmsys /etc/system

  4. Reboot the system. 


    # init 6

Example--Increasing Shared Memory Segments

The following shared memory values accommodate a system with a large amount of memory (for example, 128 MBytes) that is running a large database application. 


set shmsys:shminfo_shmmax=268435456
set shmsys:shminfo_shmmin=200
set shmsys:shminfo_shmmni=200
set shmsys:shminfo_shmseg=200
set semsys:seminfo_semmap=250
set semsys:seminfo_semmni=500
set semsys:seminfo_semmns=500
set semsys:seminfo_semmsl=500
set semsys:seminfo_semmnu=500
set semsys:seminfo_semume=100