raso Command

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Purpose

Manages Reliability, Availability, Serviceability parameters.

Syntax

raso [-p | -r] [-y] [-o Tunable [= Newvalue] ]

raso [-p | -r] [-y] [-d Tunable]

raso [-p] [-r] [-y] -D

raso [-p] [-r] [-F] -a

raso -h [Tunable]

raso [-F] -L [Tunable]

raso [-F] -x [Tunable]

Note: Multiple -o, -d, -x, and -L flags can be specified.

Description

Note: The raso command requires root authority.

The raso command is used to configure Reliability, Availability, Serviceability tuning parameters. The raso command sets or displays the current or next-boot values for all RAS tuning parameters. The raso command can also be used to make permanent changes or to defer changes until the next reboot. The specified flag determines whether the raso command sets or displays a parameter. The -o flag can be used to display the current value of a parameter or to set a new value for a parameter.

Understanding the Effect of Changing Tunable Parameters

Misuse of the raso command can cause performance degradation or operating system failure. Before modifying any tunable parameter, you should first carefully read about all of the parameter's characteristics in the Tunable Parameters section in order to fully understand the parameter's purpose. You should then ensure that the Diagnosis and Tuning sections for this parameter actually apply to your situation and that changing the value of this parameter could help improve the performance of your system. If the Diagnosis and Tuning sections both contain only "N/A", it is recommended that you do not change the parameter unless you are specifically directed to do so by AIX® development.

Flags

Item	Description
-a	Displays the current, reboot (when used in conjunction with the -r flag), or permanent (when used in conjunction with the -p flag) values for all tunable parameters, with one tunable parameter per line displayed in pairs as Tunable = Value. For the permanent option, a value is only displayed for a parameter if its reboot and current values are equal. Otherwise NONE is displayed as the value.
-d Tunable	Resets Tunable to the default value. If Tunable needs to be changed (that is, it is currently not set to its default value) and is of type Bosboot or Reboot, or if it is of type Incremental and has been changed from its default value, and the -r flag is not used in combination, Tunable is not changed and a warning displays.
-D	Resets all tunables to their default values. If any tunables that need to be changed are of type Bosboot or Reboot, or if any tunables that need to be changed are of type Incremental and have been changed from their default value, and -r is not used in combination, these tunables are not changed and a warning displays.
-F	Forces restricted tunable parameters to be displayed when the options -a, -L or -x are specified alone on the command line. If you do not specify the -F flag, restricted tunables are not included, unless they are specifically named in association with a display option.
-h Tunable	Displays help about the raso command if no Tunable parameter is specified. Displays help about the Tunable parameter if a Tunable parameter is specified.
-L Tunable	Lists the characteristics of one or all tunables, with one tunable displayed per line using the following format: NAME CUR DEF BOOT MIN MAX UNIT TYPE DEPENDENCIES -------------------------------------------------------------------- mtrc_commonbufsize 3974 3974 3974 1 5067 4KBpages D mtrc_enabled -------------------------------------------------------------------- mtrc_enabled 1 1 1 0 1 boolean B -------------------------------------------------------------------- mtrc_rarebufsize 2649 2649 2649 1 3378 4KB pages D -------------------------------------------------------------------- ... where: CUR = current value DEF = default value BOOT = boot value MIN = minimal value MAX = maximum value UNIT = tunable unit of measure TYPE = parameter type: D (for Dynamic), S (for Static), R (for Reboot),B (for Bosboot), M (for Mount), I (for Incremental), C (for Connect), and d (for Deprecated) DEPENDENCIES = list of dependent tunable parameters, one per line
-o Tunable [ =Newvalue ]	Displays the value or sets Tunable to Newvalue. If Tunable needs to be changed (the specified value is different than current value) and is of type Bosboot or Reboot, or if Tunable if it is of type Incremental and its current value is larger than the specified value, and if the -r flag is not used in combination, Tunable is not changed and a warning displays. If the -r flag is used in combination without a new value, the nextboot value for Tunable is displayed. If the -p flag is used in combination without a new value, a value is displayed only if the current and next boot values for Tunable are the same. Otherwise, NONE is displayed as the value.
-p	When the -p flag is used in combination with the -o, -d, or -D flag, changes apply to both the current and reboot values (in addition to the current value being updated, the /etc/tunables/nextboot file is updated). These combinations cannot be used on Reboot and Bosboot type parameters because the current values for these parameters cannot be changed. When the -p flag is used with the -a or -o flag without specifying a new value, values are displayed only if the current and next boot values for a parameter are the same. Otherwise, NONE is displayed as the value.
-r	When the -r flag is used in combination with the -o, -d, or -D flag, changes apply to reboot values (the /etc/tunables/nextboot file is updated). If any parameter of type Bosboot is changed, you are prompted to run the bosboot command. When the -r flag is used with the -a or -o flag and a new value is not specified, the next boot values for tunables are displayed instead of the current values.
-x Tunable	Lists the characteristics of one or all tunables, with one tunable displayed per line using the following format (spreadsheet format): `Tunable Current Default Reboot Minimum Maximum Unit Type Dependencies` where Tunable is the tunable parameter, Current is the current value of the tunable parameter, Default is the default value of the tunable parameter, Reboot is the reboot value of the tunable parameter, Minimum is the minimum value of the tunable parameter, Maximum is the maximum value of the tunable parameter, Unit is the tunable unit of measure, Type is the parameter type, and Dependencies is the list of dependent tunable parameters. If you make any change (with -o, -d, or -D) to a parameter of type Mount, it results in a warning message that the change is only effective for future mountings. If you make any change (with -o, -d or -D) to a parameter of type Connect, it results in inetd being restarted, and a warning message that the change is only effective for future socket connections. If you make any change (with -o, -d, or -D) to a parameter of type Bosboot or Reboot without -r, it results in an error message. If you make any change (with -o, -d, or -D but without -r) to the current value of a parameter of type Incremental with a new value smaller than the current value, it results in an error message.
-y	Suppresses the confirmation prompt before running the bosboot command.

If you make any change (with -o, -d or -D) to a restricted tunable parameter, it results in a warning message that a tunable parameter of the restricted-use type has been modified. If you also specify the -r or -p options on the command line, you are prompted for confirmation of the change. In addition, at system reboot, the presence of restricted tunables in the /etc/tunables/nextboot file, which were modified to a value that is different from their default value (using a command line specifying the -r or -p options), results in an error log entry that identifies the list of these modified tunables.

You can specify a modified tunable value using the abbreviations K, M, G, T, P and E to indicate units. The following table shows the prefixes and values that are associated with the number abbreviations.

Item	Description
Abbreviation	Prefix	Power of 2
K	kilo	2¹⁰
M	mega	2²⁰
G	giga	2³⁰
T	tera	2⁴⁰
P	peta	2⁵⁰
E	exa	2⁶⁰

Thus, a tunable value of 1024 might be specified as 1K.

Tunable Parameters Type

All the tunable parameters manipulated by the tuning commands ( no, nfso, vmo, ioo, schedo, and raso) have been classified into these categories:

Item	Description
Dynamic	If the parameter can be changed at any time
Static	If the parameter can never be changed
Reboot	If the parameter can only be changed during reboot
Bosboot	If the parameter can only be changed by running bosboot and rebooting the machine
Mount	If changes to the parameter are only effective for future file systems or directory mounts
Incremental	If the parameter can only be incremented, except at boot time
Connect	If changes to the parameter are only effective for future socket connections. The parameters must be of type Bosboot.

For parameters of type Bosboot, whenever a change is performed, the tuning commands automatically prompt the user to ask if they want to execute the bosboot command. For parameters of type Connect, the tuning commands automatically restart the inetd daemon.

Note that the current set of parameters managed by the schedo command only includes Dynamic and Reboot types.

Compatibility Mode

When running the raso command in the pre 5.2 compatibility mode that is controlled by the pre520tune attribute of sys 0, the reboot values for parameters, except for those of type Bosboot, are not considered because in this mode they are not applied at the boot time. See NFS tuning on the client in the Performance management guide for detailed information.

In pre 5.2 compatibility mode, setting reboot values to tuning parameters continues to be achieved by imbedding calls to tuning commands in scripts called during the boot sequence. Parameters of type Reboot can therefore be set without the -r flag, so that existing scripts continue to work.

This mode is automatically turned ON when a machine is MIGRATED to AIX 5.2. For complete installations, it is turned OFF and the reboot values for parameters are set by applying the content of the /etc/tunables/nextboot file during the reboot sequence. Only in that mode are the -r and -p flags fully functional. See Kernel Tuning in the Performance Tools Guide and Reference for more information.

Tunable Parameters

For default values and range of values for tunables, refer the raso command help (-h <tunable_parameter_name>).

Item	Description
kern_heap_noexec	Purpose: Specifies whether no-execute protection should be enabled for the kernel heap. Tuning: With protection enabled, any attempt to execute code in the protected heap will result in a kernel exception.
kernel_noexec	Purpose: Specifies whether no-execute protection should be enabled for kernel data regions. Tuning: With protection enabled, any attempt to execute code in the protected regions will result in a kernel exception.
mbuf_heap_noexec	Purpose: Specifies whether no-execute protection should be enabled for the mbuf heap. Tuning: With protection enabled, any attempt to execute code in the protected heap will result in a kernel exception.
mtrc_commonbufsize	Purpose: Specifies the memory trace buffer size for common events of Lightweight Memory Trace (LMT) which provides system trace information for First Failure Data Capture (FFDC). Tuning: The default value is based on data generation under a reference system-wide activity, hardware, and system characteristics. The range upper limit is based on the hardware and system characteristics and depends on the current value of mtrc_rarebufsize because they share the LMT resource. Recorded events are saved in system dump and/or reported through user commands.
mtrc_enabled	Purpose: Defines the Lightweight Memory Trace (LMT) state. Tuning: Value of 1 means LMT is enabled. To be effective, any change of state requires a subsequent bosboot and system reboot.
mtrc_rarebufsize	Purpose: Specifies the memory trace buffer size for rare events of Lightweight Memory Trace (LMT) which provides system trace information for First Failure Data Capture (FFDC). Tuning: The default value is based on data generation under a reference system-wide activity, hardware, and system characteristics. The range upper limit is based on the hardware and system characteristics and depends on the current value of mtrace_commonbufsize because they share the LMT resource. Recorded events are saved in system dump and/or reported through user commands.
tprof_cyc_mult	Purpose: Specifies the Performance Monitor PM_CYC and software event sampling frequency multiplier as a means to control the trace sampling frequency.
tprof_evt_mult	Purpose: Specifies the Performance Monitor PM_* event sampling frequency multiplier as a means to control the trace sampling frequency.
tprof_inst_threshold	Purpose: Specifies the minimum number of completed instructions between Performance Monitor event samples as a means to control the trace sampling frequency. Values: Default: 1000 Range: 1 to 2G-1 Type: Dynamic Diagnosis: Not applicable Tuning: Not applicable
tprof_evt_system	Purpose: Allows or restricts the non-privileged users from using the system-wide Performance Monitor event-sampling. Values: Default: 0 Range: 0, 1 Type: Dynamic Unit: Boolean Tuning: With tprof_evt_system enabled (value 1), the non-privileged users can use tprof and pmctl commands to perform system-wide Performance Monitor event-sampling. When disabled (value 0), non-privileged users can perform event-sampling for processes started with -y option of tprof and pmctl commands. In the disabled mode, non-privileged users cannot perform event-sampling of kernel and kernel extensions.

Examples

To list the current and reboot value, range, unit, type, and dependencies of all tunable parameters managed by the raso command, type the following:
```
raso -L
```
To turn off the Lightweight Memory Trace, type the following:
```
raso -r -o mtrc_enabled=0
```
To display help for mtrc_commonbufsize, type the following:
```
raso -h mtrc_commonbufsize
```
To set tprof_inst_threshold to 10000 after the next reboot, type the following:
```
raso -r -o tprof_inst_threshold=10000
```
To permanently reset all raso tunable parameters to their default values, type the following:
```
raso -p -D
```
To list the reboot level for all Virtual Memory Manager tuning parameters, type the following:
```
raso -r -a
```