Tuning journal-based backups

To help improve the performance of incremental backups, you can run journal-based backups.

About this task

Journal-based backups have the following advantages over standard incremental backups:

Journal-based backups can complete faster than standard incremental backups because they do not compare file system object attributes with information that is stored on the server. Instead, on a file system that supports journaling, changes to a file system are recorded in a locally stored journal database. The locally stored journal database entries are used to determine which objects to include in backup operations.
The benefits of using a journal-based backup do diminish if the file systems have many file changes. Journal-based backups perform best on large file systems in which many of the files do not often change.
Journal-based backups require less memory and less client disk I/O than full incremental backups.

Procedure

Use the information in the following table to help you tune journal-based backups.

Action	Explanation
Ensure that there is enough disk space on the client system to contain the journal database.	The amount of disk space that is required for the journal database depends on the number of files and directories that change between each successive journal-based backup operation.
Use default settings.	The default settings for journal size, log names and locations, file system check intervals, and other journal settings work well in most environments.
Change the default settings. Edit the tsmjbbd.ini.smp file to include or exclude file systems to monitor for changes, set the size of the journal database, and specify notification options and other settings. Save the changes to a file named tsmjbbd.ini (without the smp extension).	If the default settings do not work well in your system environment, change them. For example, by excluding file systems, you can limit the amount of data to monitor for journal-based backups. This action can improve the performance of the backups. Configuration settings for the journal service (on Windows) or journal daemon (on Linux® and AIX®) are copied to the client disk when you install the backup-archive client. The default settings are in the tsmjbbd.ini.smp file. Comments in the tsmjbbd.ini.smp file provide the documentation for the journal settings. The journal service or journal daemon uses the tsmjbbd.ini file when the journal service is started. Tips for the Windows client: You can use the configuration wizard to edit the default settings. Changes that are made to the tsmjbbd.ini file are applied dynamically. When changes are made to the settings in the file, the journal service applies the changes automatically without needing to restart the service.

Action

Explanation

Ensure that there is enough disk space on the client system to contain the journal database.

The amount of disk space that is required for the journal database depends on the number of files and directories that change between each successive journal-based backup operation.

Use default settings.

The default settings for journal size, log names and locations, file system check intervals, and other journal settings work well in most environments.

Change the default settings. Edit the tsmjbbd.ini.smp file to include or exclude file systems to monitor for changes, set the size of the journal database, and specify notification options and other settings. Save the changes to a file named tsmjbbd.ini (without the smp extension).

If the default settings do not work well in your system environment, change them. For example, by excluding file systems, you can limit the amount of data to monitor for journal-based backups. This action can improve the performance of the backups.

Configuration settings for the journal service (on Windows) or journal daemon (on Linux® and AIX®) are copied to the client disk when you install the backup-archive client. The default settings are in the tsmjbbd.ini.smp file. Comments in the tsmjbbd.ini.smp file provide the documentation for the journal settings.

The journal service or journal daemon uses the tsmjbbd.ini file when the journal service is started.

Tips for the Windows client:

You can use the configuration wizard to edit the default settings.
Changes that are made to the tsmjbbd.ini file are applied dynamically. When changes are made to the settings in the file, the journal service applies the changes automatically without needing to restart the service.

What to do next

For more information about when to use journal-based backups, see Journal-based backup Journal-based backup.