The /etc/system file provides a static mechanism for adjusting the values of kernel variables. Values specified in this file are read at boot time and are applied. Any changes made to the file are not applied to the operating system until the system is rebooted.
Prior to the Solaris 8 release, /etc/system entries that set the values of system variables were applied in two phases:
The first phase obtains various bootstrap variables (for example, maxusers) to initialize key system parameters.
The second phase calculates the base configuration by using the bootstrap variables, and all values entered in the /etc/system file are applied. In the case of the bootstrap variables, reapplied values replace the values calculated or reset in the initialization phase.
The second phase sometimes caused confusion to users and administrators by setting variables to values that seem to be impermissible or assigning values to variables (for example, max_nprocs) that have a value overridden during the initial configuration.
In the Solaris 8 release, one pass is made to set all the values before the configuration parameters are calculated.
The following /etc/system entry sets the number of read-ahead blocks that are read for file systems mounted using NFS version 2 software.
Make a copy of /etc/system before modifying it so you can easily recover from incorrect value:
# cp /etc/system /etc/system.good
If a value entered in /etc/system causes the system to become unbootable, you can recover with the following command:
ok boot -a
This command causes the system to ask for the name of various files used in the boot process. Press the carriage return to accept the default values until the name of the /etc/system file is requested. When the Name of system file [/etc/system]: prompt is displayed, enter the name of the good /etc/system file or /dev/null:
Name of system file [/etc/system]: /etc/system.good
If /dev/null is entered, this path causes the system to attempt to read from /dev/null for its configuration information and because it is empty, the system uses the default values. After the system is booted, the /etc/system file can be corrected.
For more information on system recovery, see System Administration Guide, Volume 1.