12.1.2 Designing the disks used by the audit trail facility

This section explains how to design the disks (storage areas) used by the audit trail facility.

The audit trail facility uses the following directories:

Audit trail directory
Audit trail storage directory
Audit trail long-term storage directory

We recommend that you create each directory on a dedicated disk (storage area). If you create them all on the same disk (storage area), I/O operations are concentrated on that disk (storage area), potentially degrading the processing performance of the HADB server.

Note that the process of referencing audit trail information does not involve writing to the audit trail file. Therefore, we recommend that you create the following two directories on write-once disks (storage areas). An advantage of this approach is that the audit trail files on write-once disks (storage areas) cannot be tampered with.

Audit trail storage directory
Audit trail long-term storage directory

In selecting the type of disk (storage area) on which to store each directory, we recommend that you consider factors including how often the data is referenced and how long the data is retained. For example, the audit trail files in the audit trail storage directory are likely to be referenced quite frequently. For this purpose, you might consider using a flash drive which offers faster access. Because the audit trail files on the audit trail long-term storage directory are accessed infrequently and stored for a long time, a hard disk or magnetic tape might be more suitable than a flash drive.

The following figure shows an example configuration of the disks (storage areas) used by the audit trail facility. In this example, audit trail files are kept in the audit trail storage directory for one year. Those audit trail files are then stored in the audit trail long-term storage directory for a further nine years.

Figure 12‒1: Example disk (storage area) configuration used by audit trail facility

For details about how to determine the space requirements of the disks (storage areas) used by the audit trail facility, see the following subsections:

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