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systune(1M)							   systune(1M)

NAME    [Toc]    [Back]

     systune - display and set tunable parameters

SYNOPSIS    [Toc]    [Back]

     systune [ -bfir ] [ -n name ] [ -p	rootpath ]
	   [ variable [	value ]	]

DESCRIPTION    [Toc]    [Back]

     systune is	a tool that enables you	to examine and configure your tunable
     kernel parameters.	 systune can adjust some parameters in real time and
     informs you if you	need to	reboot your system after reconfiguration.  It
     saves the reconfigured kernel in /unix.install, unless the	-f option is

     systune has two modes: interactive	and noninteractive.  Interactive mode
     allows you	to query information about various portions of tunable
     parameters	or to set new values for tunable parameters.  Some parameters
     can be changed while the system is	running, and some require a new	copy
     of	the kernel to be booted.  To enter interactive mode, use the -i
     option.  In noninteractive	mode, systune displays the values of one
     tunable parameter or group	of tunable parameters, or allows the value of
     one tunable parameter to be changed.  Note	that you will still be
     prompted for a confirmation when changing a parameter in noninteractive
     mode.  To avoid interacting with the confirmation you must	use additional
     commands, for example:

	 # echo	y | systune nproc 400

     Noninteractive mode is the	default.

     The options are:

     -b	     Both target kernel	and the	running	system are updated with	the
	     new values	that you specified, if the new values are within the
	     legal range for the parameter specified in	/var/sysgen/mtune.
	     The new values with the corresponding tunable variables are also
	     added into	/var/sysgen/stune file.	 This is the default behavior.

     -f	     This option forces	systune	to not save the	reconfigured kernel in
	     /unix.install.  By	default, systune tests to see if /unix.install
	     exists and	whether	it is identical	to the running system.	If it
	     is	identical, systune makes any changes in	/unix.install;
	     otherwise,	systune	copies the current /unix kernel	or the kernel
	     specified by the -n option	to /unix.install and makes all changes
	     to	the copied kernel.  If the copy	fails for any reason, such as
	     lack of disk space	or the presence	of the -f option, the
	     currently running kernel is changed.

     -i	     Run systune in interactive	mode.  When systune is invoked in
	     interactive mode, no parameter values are immediately displayed.
	     Instead, you see the systune prompt:

									Page 1

systune(1M)							   systune(1M)


	     The commands available in interactive mode	are described below.

     -n	name This option specifies an alternate	kernel name to tune in place
	     of	/unix.

     -p	rootpath
	     If	you specify this option, rootpath becomes the starting
	     pathname for systune to check for /var/sysgen/stune and
	     /var/sysgen/mtune.	 The default rootpath directory	is /.

     -r	     The new values change on the running system only.	If the tunable
	     parameter can not be changed on the running system, nothing is
	     affected.	The default is -b.

     If	the name of a variable is specified on the command line, its current
     value is displayed.  If the name of a group is specified on the command
     line, the names and values	of all variables in that group are displayed.
     If	the name of a variable and a value are specified on the	command	line,
     the variable's value is changed after verification	and confirmation.

     The systune commands available in interactive mode	are:

     quit    Quit systune immediately.	Any changes you	have made up to	that
	     point are saved and cannot	be discarded.  You must	go through and
	     change back any parameters	that you do not	wish to	be changed.

     all     Print information on all tunable parameters.  This	command
	     displays the same information as systune invoked in
	     noninteractive mode.

     help    Show all the built-in commands and	group names.  systune lists
	     two commands (help	and all) and the groups	of kernel tunable
	     parameters.  Each group of	tunable	parameters is organized	so
	     that related parameters are kept together.	 For example, the
	     numproc parameter group contains parameters related to the	number
	     of	processes allowed to run on the	system at any given time.  Its
	     parameters	are:

		  ncsize = 808 (0x328)
		  ncallout = 40	(0x28)
		  callout_himark = 332 (0x14c)
		  ndquot = 808 (0x328)
		  nproc	= 300 (0x12c)

	     Display information for all the tunable parameters	in this	group
	     along with	their values in	decimal	numerals and in	hexadecimal

									Page 2

systune(1M)							   systune(1M)

	     Display information for this tunable parameter only.

     parameter_name newvalue
	     Set the specified tunable parameter to the	new value.  For
	     example, to raise the nproc parameter in the numproc parameter
	     group from	300 to 400, follow this	example:

		  systune-> nproc 400
		  nproc	= 300 (0x12c)

		  Do you really	want to	change nproc to	400 (0x190)? (y/n) y

		  In order for the change in parameter nproc to	become
		  effective, /unix.install must	be moved to /unix and the
		  system rebooted.

	     This message tells	you that the change does not take effect until
	     a new kernel with the new value is	running	on your	system.
	     systune always prints a message to	inform you if you need to
	     reboot your system	for a kernel change to take effect.

	     systune makes all requested changes to the	kernel in three
	     places, if	possible.  (Nondynamically adjustable parameters can
	     be	changed	in only	two out	of three places.) The parameters are
	     changed in:

	     o	the running kernel image on the	workstation
	     o	the /unix or /unix.install file
	     o	the /var/sysgen/stune file

	     Some sanity checking is performed on the modified kernel
	     parameters	to help	prevent	the creation of	kernels	that will not
	     function correctly.  This checking	is performed both by systune
	     and by the	lboot(1M) command.  For	example, some variables	have
	     preset minimum and	maximum	values.	 Any attempt to	change the
	     variable beyond these threshold values results in an error
	     message, and the variable is not changed.

BUGS    [Toc]    [Back]

     When the system calculates	its default value for a	systune, the resulting
     value may be outside the valid range provided by the mtune	file.  For
     example, if you set mbmaxpages to 0 (i.e. ask system for default value)
     then on a 32-bit system with 256M of RAM the default is set to 16384.
     However the maximum allowed by mtune is 8192.  In this example, the
     system will configure mbmaxpages to 16384 from the	default	of 0, but it
     is	not possible to	assign mbmaxpages > 8192 directly from systune because
     of	the restriction	in mtune.

									Page 3

systune(1M)							   systune(1M)

     /var/sysgen/mtune/*   system tunable parameters
     /var/sysgen/stune	   local settings for system tunable parameters

SEE ALSO    [Toc]    [Back]

     autoconfig(1M), lboot(1M),	mtune(4), stune(4).

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