12.1.4 Estimating the compressibility of audit trail files
You can use the gzip command of the OS to compress audit trail files. This allows you to reduce the file size of the audit trail files stored in the following directories:
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Audit trail storage directory
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Audit trail long-term storage directory
To estimate the disk space required by the audit trail facility when the gzip command will be used to compress audit trail files, you first need to determine the compressibility of the audit trail files.
Use one of the following methods to determine the compressibility of the audit trail files:
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Use the gzip command to compress an audit trail file output in a small-scale test environment with the audit trail facility enabled, and check the compression ratio of the resulting file
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Assume a compressibility of 0.25 (that is, audit trail files are compressed to one quarter of their original size)
The compressibility of audit trail files varies widely depending on the HADB server environment and on the SQL statements, commands, and other operations executed by users. For this reason, we recommend that you use the first of these methods. If you are unable to prepare a test environment, use the second method.