Veritas™ File System 5.0.1 Programmer's Reference Guide

For example, an incremental backup application can scan the FCL file to
determine which files have been added or modified since the file system was
last backed up.
■ Configure the FCL to track additional information, such as file opens, I/O
statistics, and access information, such as user ID.
You can then use this information to gather the following data:
■ Space usage statistics to determine how the space usage for different types
of data.
■ Usage profile for the different files on a file system across different users
to help determine which data has been recently accessed and by whom.
Space usage
You can use the FCL file to track space usage when a file system gets close to being
full. The FCL file can be searched for recently created files (file creates) or write
records to determine newly added files or existing files that have grown recently.
Depending on the application needs, the search can be done on the entire FCL file,
or on a portion of the FCL file corresponding to a specific time frame. Additionally,
you can look for files created with particular names. For example, if users are
downloading *.mp3 files that are taking up too much space, the FCL file can be
read to find files created with the name *.mp3.
Full system scan reductions
VxFS creates and logs an FCL record for every update operation performed on an
FCL-enabled file system. These operations include creates, deletes, rename, mode
changes, and writes. Therefore, incremental backup applications or applications
that maintain an index of a file system based on the filename, file attributes, or
content can avoid a full system scan by reading the FCL file to detect the files that
have changed since the previous backup or previous index update.
File history traces
You can trace a file’s history by scanning the FCL file and coalescing FCL record
sequences for a file. You can also use the related FCL records from a file’s creation,
attribute changes, write records, and deletion to track the file’s history.
File Change Log logging activation
By default, FCL logging is deactivated and can be activated on a per-file system
basis using the fcladm command.
19File Change Log
About the File Change Log file