Day
Light Saving Change in USA -
Summary of changes with links to patches and information. -
Application
Monitoring - Challenges
, best practices and implementation of application monitoring is
discussed.
- Unix
Commands - A
quick reference to commonly used unix commands .
- Solaris
Network Configuartion -
Simplified
: Quick reference to setting up network in Solaris
system
- Performance
Monitoring - iostat , vmstat & netstat -
Introduction to
performance monitoring tools with example and
command syntax.
- crontab
in Unix
- A Quick
Reference to setting up and using cron jobs in unix
.
- Veritas
Volume Manager-1:
- Using vxdiskadm to
add & manage disks & disk groups
.
- Veritas
Volume Manager-2:
- Using vxassist to
create ,configure & manage volumes .
- Admin's
Guide to Solstice Disk Suite:
Complete practical reference including root
mirroring and trouble shooting.
- Securing
Solaris :
- A few suggestions to
make your Solaris system secure from internal and
external intrusion.
-
- Solaris
Installation
- Step by step guide
to Solaris Installation.
- Jumpstart
Server
- Network
installation of Solaris over one or multiple
systems.
- Booting
Process
- Details of Solaris
booting process.
- Booting
Problems in Solaris
- Common booting
related error messages and their possible solution
- DNS
Server
- Setting up DNS
server
- Trouble
Shooting DNS Some
of the configuration and nslookup related errors
explained.
- NIS+
- Server , Clients
setup and commands.
- OpenBoot
Parameters
- Reference table of
important parameters and their values.
- Solaris
Error Messages
- Alphabetical listing
of common Solaris Error Messages and their explanation
- Checking
& Repairing File systems with fsck
fsck
operation ,syntax and explanation of some common
error messages
- Vi
Quick Reference
- vi basics for
reference
- explanations.
-
- Open Directory
- Unix
, Solaris
Administration
- Sun.com
- BigAdmin
-
-
-
- FAQs
- unix
, unix
programming , VI
,Sendmail ,
Bind
- ssh
,BASH
,Security,
Secure
unix programming,
Unix socket
- SCSI
- Solaris
2 ,
Solaris
x86 ,NIS+ FreeBSD
,RedHat
, HPUX
- :
- Unix
- Unix
History and timeline ,
- Overview
of the UNIX
- Microsoft
Windows NT Server 4.0 versus UNIX
- Overview
of Unix Commands
- Unix
for advance Users ,
- Unix
Bourne Shell Guide with Ksh ,
- Korn
Shell
- BASH
reference Guide,
- :
- Solaris
Documentation
- Solaris
7 System Administration Collection
- Solaris
8 System Administrator Collection
- Solaris
9 System Administartion Collection
- Creating
Solaris Packages
- Multibooting
Solaris
- :
- Sun
- Sun
System Handbook
- Sun
Hardware Info.
- :
- Documentation
Home
- Sun
, BSD ,Linux
,Hp,Veritas
- :
- Patches &
Softwares
- Solaris
Patches ,
- Solaris
Freeware ,
- GNU
Software,
- big
brother ,
- webmin
.com ,
- bugzilla.org
- :
- Certification
Info
- Sun
,Red
Hat , HP
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Booting process in Solaris
what happens when a system boots up
Understanding the booting process is
important in the sense that you can get a clear idea when a system faces a
booting problem if you are familiar with the booting sequence and steps
involved. You can thereby isolate a booting phase and quickly resolve the
issues.
Booting process in Solaris can be divided in to different phases for ease of study . First phase starts at the time of switching on the machine and is boot prom level , it displays a identification banner mentioning machine host id serial no , architecture type memory and Ethernet address This is followed by the self test of various systems in the machine.
This process ultimately looks for the default boot device and reads the boot program from the boot block which is located on the 1-15 blocks of boot device. The boot block contains the ufs file system reader which is required by the next boot processes.
The ufs file system reader opens the boot device and loads the secondary boot program from
/usr/platform/`uname –i`/ufsboot ( uname
–i expands to system architecture type)
The boot program above loads a platform specific kernel along with a generic solaris kernel
The kernel initialize itself and load modules which are required to mount the root partition for continuing the booting process.
The booting process undergoes the
following phases afterwards :
- 1) init
phase
- 2) inittab
file
- 3) rc
scripts & Run Level
- 4.) Next Steps
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INIT
phase
Init phase is started by the execution of /sbin/init program and
starts other processes after reading the /etc/inittab file as per the
directives in the /etc/inittab file .
Two most important functions of init are
a) It runs the processes to bring the system to the default run level
state ( Run level 3 in Solaris , defined by initdefault parameter in
/etc/inittab )
b) It controls the transition between different run levels by
executing appropriate rc scripts to start and the stop the processes
for that run level.
/etc/inittab file
This file states the default run level and some actions to be performed while
the system reaches up to that level. The fields and their explanation are as
follows :
S3:3:wait:/sbin/rc3 > /dev/console 2>&1 < /dev/console
S3 denotes a identification if the line
3 is run level
wait is action to be performed
/sbin/rc3 is the command to be run.
So the fields in the inittab are
Identification : run level : action : process
The complete line thus means run the command /sbin/rc3 at run level 3 and wait
until the rc3 process is complete.
The action field can have any of the following keywords :
Initdefault : default run level of the system
Respawn : start and restart the process if it stops.
Powerfail : stop on powerfail
Sysinit : start and wait till console in accessible .
Wait : wait till the process ends before going on to the next line.
RC scripts &
Run
Levels
Rc scripts performs the following functions :
a) They check and mount the file systems
b) Start and stop the various processes like network , nfs etc.
c) Perform some of the house keeping jobs.
System goes in to one of the following run level after booting depending on default run level and the commands issued for changing the run level to some other one.
0 Boot prom level ok> or > prompt in Sun.
1 Administrative run level . Single user mode
2 Multiuser mode with no resource sharing .
3 Multiuser level with nfs resource sharing
4 Not used
5 Shutdown & power off (Sun 4m and 4u architecture )
6 Reboot to default run level
S s Single user mode user logins are disabled.
Broadly speaking the running system can be in any of the folloing state
Single user – Minimum processes running , user logins disabled and root password is required to gain access to the shell .
Multiuser - All system processes are running and user logins are permitted
Run level of a desired state is achieved by a number of scripts executed by the rc program the rc scripts are located in /etc/rc0.d , /etc/rc1.d , /etc/rc2.d , /etc/rc3.d &
/etc/rcS.d directories . All the files of a particular run level are executed in the alphanumeric order .Those files beginning with letter S starts the processes and those beginning with K stops the processes.
These files are hard linked to the files in /etc/init.d in order to provide a central location for all these files and eliminating the need to change the run level in case these scripts needs to be run separately . The files in
/etc/init.d directory are without any S , K and numeric prefix instead a stop / start argument has to be supplied whenever these scripts are to be executed .
By default system has a number of rc scripts needed for run level transition but sometimes it becomes necessary to start some custom scripts at the booting time and turn them off at the shutdown . Custom scripts can be put in any of the required rc directory but following major considerations has to be kept in mind :
- The sequence number of the file should not conflict with other files.
- The sevices needed should be available by previously executed scripts.
- File should be hard linked to the /etc/init.d directory
.
- The system looks for only those files beginning with letter K & S , any thing else is ignored , therefore, to make a file inactive simply changing uppercase K or S to lower case will cause system to ignore it .
6.
Next Steps
This article covered Solaris
booting process . Booting process is the starting task of all the
sysadmin activities to be carried out later like user creation , network
configuration etc. While most of the sysadmin aspects are covered in this site
still it pays to have a system administration book handy .
There are some good books available on unix and Solaris administration
which broaden your understanding of Solaris & unix and there by helping
in your day today work and providing you satisfaction of work.
Following books available for online
buying from Amazon.com . You should have following two books in your
bookshelf for ready reference if you are involved in Unix system
administration .
If you are interested in knowing more about unix its architecture
& internals you can choose the books from following list of selected best
books in this field :
If you already own these books the
amazon display panel below shows some of the best-selling books for System
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You can show your appreciation by
buying the books for yourself and encouraging the friends to buy
using amazon links below or anywhere at adminschoice.com
or besttechbooks.com . Thanks
for your appreciation in advance.
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by Æleen Frisch