Availability Guide for Change Management

Making Application Subsystem Changes Online

Availability Guide for Change Management–125506

4-16

Making Changes to NonStop TM/MP Online

You may need to change your NonStop TM/MP configuration to accommodate business

growth or to respond to changing business factors requiring an increased or decreased

level of protection for your database.

This subsection:

•

Provides a brief overview of NonStop TM/MP

•

Describes the changes you can make to NonStop TM/MP online

Overview of NonStop TM/MP

The NonStop TM/MP product protects databases in OLTP environments using its main

functional component, the Transaction Management Facility (TMF) subsystem. The

TMF subsystem manages database transactions, keeps track of database activity through

audit trails, and provides database recovery methods.

NonStop TM/MP is required by NonStop SQL/MP. The NonStop TM/MP subsystem

also supports the NonStop TS/MP product by recording information about transactions.

NonStop SQL/MP and NonStop TS/MP are described earlier in this section.

Transactions

The fundamental component of the TMF subsystem is a programmatic construct called a

transaction. A transaction is an explicitly delimited operation or set of related

operations that alters the content of a database. If an error occurs while a transaction is

in progress, the TMF subsystem backs out whatever partial changes were made to the

database, leaving the database in a consistent state.

Audit Trails

Before a transaction permanently commits its changes to the database, information about

the affected database rows or records is written to the audit trail. An audit trail is a

series of files containing audit records and TMF control records. An audit trail can span

up to 16 volumes.

There is one master audit trail (MAT) in each TMF subsystem. In addition, each TMF

subsystem can have up to 15 auxiliary audit trails. These audit trails contain audit

records in addition to those in the MAT.

When you configure the MAT, you specify the names of the disk volumes that will

receive audit information. These disk volumes are called active audit volumes. The set

of audit-trail files on an active audit volume are collectively referred to as the active

audit trail. You can also specify disk volumes to use if all audit-trail files become

filled. These are called overflow audit volumes.

Audit dumps preserve copies of audit-trail files for file recovery. Audit-dump processes

copy audit-trail files from active or overflow audit volumes to tape or disk.

Note. For a more complete overview of NonStop TM/MP, see the Introduction to NonStop

Transaction Manager/MP (TM/MP).