Commands Reference, Volume 1

cthatstune Command

Purpose

Changes the topology services subsystem tunable parameters at run time.

Syntax

cthatstune [-f [network]:frequency] [-s [network]:sensitivity] [-p priority] [-l log_length] [-m pin_object] [-r] [-v]

cthatstune [-h]

Description

The cthatstune command changes the topology services subsystem tunable parameters at run time. The topology services subsystem has two types of tunable parameters:

subsystem-wide

Affects the behavior of the topology services subsystem. This type includes the fixed priority level, maximum log file length, and the object to be pinned in main memory.

per-network

Affects the behavior of each network. This type includes the heartbeat frequency and sensitivity.

The cthatstune command changes the parameters in the cluster data. The new values will not take effect until the topology services daemon reads in the new values from the cluster data. A refresh operation can be used to tell the topology services daemon to read the new values from the cluster data. You can start a refresh operation by issuing the cthatsctrl -r command or the cthatstune -r command on one of the nodes in the cluster.

In addition to the real values, two special values: VIEW and DEFAULT, can be used to display the current setting and to use the default value of the tunable parameter, respectively.

For per-network tunable parameters, in addition to the network name, an empty network name or the special network name ALL can be used to specify that the value following the network name should apply to all networks.

Flags

-f [network]:frequency[,[network]:frequency[,[network]:frequency...]]

Specifies the interval in seconds between heartbeats, or heartbeat frequency, for a particular network or multiple networks. Multiple networks should be separated by commas (,).

The value of frequency can be any integer from 1 to 30. The default value is 1.

-h

Writes the command's usage statement to standard output.

-l log_length

Specifies the maximum log file length (in number of lines).

The value of log_length can be any integer from 2000 to 1,000,000. The default value is 5000.

-m pin_object [,pin_object...]

Specifies the object to be pinned in main memory. Valid values are:

NONE: Does not pin any object in main memory.
TEXT: Specifies the TEXT object to be pinned in main memory.
DATA: Specifies the DATA object to be pinned in main memory.
STACK: Specifies the STACK object to be pinned in main memory.
PROC: Specifies that all pinnable objects should be pinned in main memory. This is the default value.

-p priority

Specifies the fixed priority level. The value of priority can be 0, which means "do not run in fixed priority level," or any integer from 1 to 80. The default value is 30.

-r

Refreshes and applies the new tunables.

-s [network]:sensitivity[,[network]:sensitivity[,[network]: sensitivity...]]

Specifies the maximum number of missing heartbeats. If this maximum is exceeded, the topology services daemon considers the peer to be inactive.

The value of sensitivity can be any integer from 4 to 40. The default value is 4.

-v

Provides verbose output.

Security

You must have root authority to run this command.

Exit Status

0: Indicates that the command completed successfully.
a non-zero value: Indicates that an error occurred.

Restrictions

This command is valid in a peer domain only.

Standard Output

When the -h flag is specified, this command's usage statement is written to standard output. All verbose messages are written to standard output.

Standard Error

This command writes any error messages to standard error.

Examples

To change the fixed priority level to 40, view the current setting of the maximum log file length, and pin default objects in main memory, without making the new setting take effect immediately, enter:
```
cthatstune -p 40 -l VIEW -m DEFAULT
```
To make the new setting (previously changed by cthatstune) take effect, enter:
```
cthatstune -r
```
To change the fixed priority level to normal, pin program and data segments in main memory, and make the new settings take effect immediately, enter:
```
cthatstune -p 0 -m TEXT,DATA -r
```
To change the heartbeat frequency of filesys_net to 2 and all other networks to 4, change the sensivity of all other networks to the default value, and make the new settings take effect immediately, enter:
```
cthatstune -f filesys_net:2,:4 -s :DEFAULT -r
```
To change the heartbeat frequency of filesys_net to the default value and service_net to 3, change the sensitivity of all networks to 8, pin the entire topology services subsystem in main memory, and make the new settings take effect immediately, enter:
```
cthatstune -f filesys_net:DEFAULT,service_net:3 -s :8 -m PROC -r
```
You can also do this using the following method:
```
cthatstune -f filesys_net:DEFAULT,service_net:3
cthatstune -s :8
cthatstune -m PROC
cthatstune -r
```

Location

/usr/sbin/rsct/bin/cthatstune: Contains the cthatstune command

Related Information

Commands: cthatsctrl, lssrc