TMF Planning and Configuration Guide (G06.24+)

Doing an Initial Configuration

HP NonStop TMF Planning and Configuration Guide—522416-004

2-2

Adding the Master Audit Trail (MAT)

You use the ADD AUDITTRAIL command to add the master audit trail (MAT) to your

system.

When configuring a typical TMF environment, the only MAT parameter values you

must configure are the audit-trail file size and the number of audit trail files on the

active-audit volume.

Audit-Trail File Size

You use the FILESIZE parameter of the ADD AUDITTRAIL command to specify the

desired audit-trail file size.

The maximum recommended file size for an audit trail is 95% of the capacity of one

tape (for example, one tape cartridge or tape reel) to which you direct the audit dumps.

Otherwise, audit dumps might require more than one tape. Such audit dumps waste

valuable resources; they double the physical storage and media handling

requirements.

Tape capacity depends on several factors, including the make and model of tape drive

you are using, the tape density, and the compression. Compression is variable and

depends on the type of data. For an initial estimate of tape capacity, refer to the

manual for your tape drive and use the lowest possible compression ratio to calculate

the capacity. To optimize the use of tapes, further experimentation will be necessary.

The minimum recommended file size is 5 megabytes.

If the daily audit generation rate is expected to exceed the capacity of one tape, use

the recommended maximum file size; in all other cases, use the daily audit generation

rate as the file size (this gives you approximately one audit dump per day).

Your service provider can help you estimate the anticipated audit generation rate. This

rate is highly variable depending on your application and data, and you might need to

experiment with your TMF configuration to find the optimal rollover frequency for your

application. If you are running applications that have already been functional under a

previous release of TMF, the audit generation rates from that environment will be close

enough to use in planning for the D46 TMF environment.

If you are designing new applications, however, you should consult your systems

analysts and application programmers to estimate the following:

1. How many disk writes, typically, would be involved in each transaction

2. How many bytes of data, typically, would be transferred in each disk write

3. How many transactions, typically, would occur during each business hour

Table 2-1 summarizes these guidelines.