Web Services Data Access Engine configuration parameters

This section discusses how to change Web Services Data Access Engine system configuration parameters using the SA Client or by editing the configuration file.

You must restart the Web Services Data Access Engine after changing any system configuration parameters.

• Changing a system configuration parameter
• Web Services Data Access Engine configuration file
• Increasing the Web Services Data Access Engine maximum heap memory allocation

Changing a system configuration parameter

This section describes how to change some of the system configuration parameters with the SA Client. Other parameters can only be changed by editing a configuration file as described in Web Services Data Access Engine configuration file.

To change a system configuration parameter for the Web Services Data Access Engine in the SA Client:

1. Select the Administration tab in the SA Client.
2. From 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 Web Services Data Access Engine. This displays the system configuration parameters for this component.
4. Locate and modify the system configuration parameters you want to change.
5. Select Revert to discard your changes or the Save button to save your changes.
6. Restart the Web Services Data Access Engine with the following command:

   /etc/init.d/opsware-sas restart twist

Web Services Data Access Engine configuration file

The Web Services Data Access Engine configuration file includes properties that affect the server side of the SA Web Services API 2.2. (These properties are not displayed in the SA Client.) The fully qualified name of the configuration file is as follows:

/etc/opt/opsware/twist/twist.conf

During an upgrade of SA, the twist.conf file is replaced, but the twist_custom.conf file is preserved. When you upgrade to a new version of SA, to retain the configuration settings, you must edit the twist_custom.conf file. The properties in twist_custom.conf override those specified in twist.conf. The UNIX twist user must have write access to the twist_custom.conf file.

To change a property defined in the configuration file:

1. Edit the twist.conf file with a text editor.
2. Save the changed file.
3. Restart the Web Services Data Access Engine on the server.

You must belong to the Administrators group (admin) to modify the twist.conf file. Once the file is changed, the Web Services Data Access Engine must be restarted to apply the changes.

The following table lists the properties of the configuration file that affect the SA Web Services API 2.2. Several of these properties are related to the cache (sliding window) of server events. SA maintains a sliding window (with a default size of two hours) of events describing changes to SA objects. This window makes enables software developers to update a client-side cache of objects without having to retrieve all of the objects. For more information, see the API documentation for EventCacheService.

Configuration File for SA Web Services API 2.2

Property	Default	Description
twist.webservices.debug.level	1	An integer value that sets the debug level for the SA Web Services API on the server side. Allowed values: 0 - basic info 1 - more detailed information 2 - stack trace 3 - for printing the server event cache entries whenever there is an item added to the cache.
twist.webservices.locale.country	US	The country Internationalization parameter for the Localizer utility. Currently only the US code is supported.
twist.webservices.locale.language	en	Sets the language Internationalization parameter for the Localizer utility. Currently only the en code is supported.
twist.webservices.caching.windowsize	120	In minutes, the size of the sliding window maintaining the server event cache.
twist.webservices.caching.windowslide	15	In minutes, the sliding scope for the window maintaining the server event cache.
twist.webservices.caching.safetybuffer	5	In minutes, the safety buffer for the sliding window maintaining the server event cache.
twist.webservices.caching.minwindowsize	30	In minutes, the minimum size of the sliding window that maintains the server event cache.
twist.webservices.caching.maxwindowsize	240	In minutes, the maximum size of the sliding window that maintains the server event cache.

Increasing the Web Services Data Access Engine maximum heap memory allocation

As data size in a multimaster mesh grows, you may find that you must increase the maximum heap memory allocation for the Web Services Data Access Engine (twist). The default value is 4096Mb. To do so, perform the following tasks:

1. Using a text editor, open the file:

   /etc/opt/opsware/twist/twist_custom.conf

2. Modify the following entry to the required allocation:

   twist.mxMem=<memory size>

   where memory size corresponds to -Xmx<memory size>.

   For example, twist.mxMem=2048m would give the Web Services Data Access Engine a maximum of 2048 megabytes of heap memory. This change is preserved even after an upgrade. If you leave this twist_custom.conf parameter blank, the default value (4096m) specified in twist.sh is used.