Run Levels
A system's run level (also known as an init state) defines what services and
resources are available to users. A system can be in only one run level at a time.
The Solaris software environment has eight run levels, which are described in Table 6-1.
The default run level 3 is specified in the /etc/inittab file.
Table 6-1 Solaris Run Levels
|
Run Level
|
Init State
|
Type
|
Use This Level ...
|
|
0
|
Power-down
state
|
Power-down
|
To shut down the operating system so that it is safe to turn off power
to the system.
|
|
1
|
Administrative state
|
Single-user
|
To access all available file systems
with user logins allowed. The terminal from which you issue this command becomes the Console.
|
|
2
|
Multiuser state
|
Multiuser
|
For normal operations. Multiple users can access the system and the entire file system.
All daemons are running except for NFS server and syslog.
|
|
3
|
Multiuser with
NFS resources shared
|
Multiuser
|
For normal operations with NFS resource-sharing available.
|
|
4
|
Alternative multiuser state
|
|
This level is currently unavailable.
|
|
5
|
Power-down state
|
Power-down
|
To shut down the
operating system so that it is safe to turn off power to the system. If possible, automatically turn off
system power on systems that support this feature.
|
|
6
|
Reboot state
|
Reboot
|
To shut down the system
to run level 0, and then reboot to multiuser state (or whatever level is the default in the inittab file).
|
|
s or S
|
Single-user state
|
Single-user
|
To run as a single user with all file
systems mounted and accessible.
|
How to Determine a System's Run Level
Display run level information by using the who -r command to determine a system's
run level.
Use the who -r command to determine a system's current run level for any level
except run level 0.
Example--Determining a System's Run Level
$ who -r
. run-level 3 Oct 26 15:04 3 0 S
$
|
|
run level 3
|
Identifies the current run
level.
|
|
Oct 26 15:04
|
Identifies the date of last run level change.
|
|
3
|
Is the current run level.
|
|
0
|
Identifies the number of times at this
run level since the last reboot.
|
|
S
|
Identifies the previous run level.
|
