Database Access Engine configuration parameters

The configuration parameters are described in the following table.

Database Access Engine configuration parameters

Parameter	Type	Allowed Values	Default	Description
cpu.affinity.check.interval	INTEGER	0-MAXINT	900	This value specifies how frequently (expressed in seconds) the cronbot checks for change for cpu.affinity values . This avoids the need for SA component reset after you change the value. Since a cronbot is already running with the current settings, any change in the interval will take place after the current cpu.affinity.check.interval setting expires.
cpu.affinity *	NUMBER	-2 - $NUMBER_OF_CPUS_ON_THE_MACHINE-1	-2	The ID of the CPU the Database Access Engine component will be affined (bound) to.
* In Linux , the CPUs are numbered starting from 0 to $NUMBER_OF_CPUS_ON_THE_MACHINE - 1. Using any value between 0 and $NUMBER_OF_CPUS_ON_THE_MACHINE - 1 will forcibly bind Database Access Engine (aka SPIN) to the CPU having index value = cpu.affinity, without checking for any other process that could be bound on the same CPU. Attention: Binding multiple processes to the same CPU can affect performance. Therefore, be sure if you want to use it. It is recommended to use -2 since this will trigger a safe heuristic to identify the most suitable CPU to bind the Database Access engine to. If no suitable CPU is found (every CPU on the Linux server have at least one process bound to it) the heuristic will not operate any CPU binding and will notify this in the Database Access Engine log file (/var/log/opsware/spin/daemonbot.out) Using -1 will disable any existing CPU binding for Database Access Engine.

Changing the CPU Affinity from Database Access Engine

CPU affinity is the ability in Linux to bind a process to a specific CPU to improve performance of that process. This feature is leveraged at the SA mesh level and then implemented on all SA mesh components. The CPU affinity parameter is enabled in SA by default and set to values found to be suitable for common use. If required, you can change the settings. This section describes how to change the CPU affinity from the Database Access Engine.

Changing the system configuration parameters

This section describes how to change the configuration parameters for the Database Access Engine in the SA Client.

1. Click the Administration tab in the SA Client.
2. In the navigation pane select System Configuration > Configuration Parameters. This displays the SA components, facilities and realms that have system configuration parameters.
3. From the list of SA components, select Data Access Engine component.
4. Locate and modify the system configuration parameters you want to change.
5. Select Revert to discard your changes or Save to save your changes.

No reset is required for Database Access Engine (aka SPIN). You need to reset only if you have changed cpu.affinity from cpu.affinity.check.interval variables.