Veritas™ File System 5.0.1 Programmer's Reference Guide

The FCL file is usually a sparse file containing the FCL superblock and the FCL

records. The first information block in the FCL file is the FCL superblock. This

block may be followed by an optional hole as well as the FCL records which contain

information about the changes in the file system.

Figure 2-1 depicts the FCL file format.

Figure 2-1

FCL file format

Superblock

Record

Offset 0x0

First Offset File System Block Boundary

File System Block Boundary

Record

Last Offset

File Change Log superblock

Changes to files and directories in the file system are stored as FCL records. The

superblock, which is currently stored in the first block of the FCL file, describes

the state of the FCL file.

The superblock indicates the following:

■ Whether FCL logging is enabled

■ What time it was activated

■ The current offsets of the first and last FCL records

■ The FCL file version

■ The event mask for the set of events currently being tracked

■ The time that the event mask was last changed

The FCL file containing just the superblock is created when FCL is first activated

using the fcladm on command. The superblock gets removed only when the FCL

file is removed using the fcladm rm command.

When the FCL is activated using fcladm on, the state in the superblock and its

activation time are changed. Whenever any file system activity results in a record

being appended to the FCL file, the last offset gets updated.

21File Change Log

About the File Change Log file