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About online backup

VxFS provides online data backup using the snapshot feature. An image of a mounted file system instantly becomes an exact read-only copy of the file system at a specific point in time. The original file system is called the snapped file system, the copy is called the snapshot.

When changes are made to the snapped file system, the old data is copied to the snapshot. When the snapshot is read, data that has not changed is read from the snapped file system, changed data is read from the snapshot.

Backups require one of the following methods:

• Copying selected files from the snapshot file system (using find and cpio)
• Backing up the entire file system (using fscat)
• Initiating a full or incremental backup (using vxdump)

See Online backup using file system snapshots.