VERITAS File System 4.1 Administrator's Guide

Chapter 6 117
6 Online Backup Using File System
Snapshots
This chapter describes the online backup facility provided with the VERITAS File System
(VxFS). The snapshot feature of VxFS can be used to create a snapshot image of a mounted
file system, which becomes a duplicate read-only copy of the mounted file system. This
chapter also provides a description of how to create a snapshot file system and some examples
of backing up all or part of a file system using the snapshot mechanism.
The following topics are covered in this chapter:
• Snapshot File Systems
• Using a Snapshot File System for Backup
• Creating a Snapshot File System
• Making a Backup
• Performance of Snapshot File Systems
• Differences Between Snapshots and Storage Checkpoints
• Snapshot File System Internals
— Snapshot File System Disk Structure
— How a Snapshot File System Works