Veritas File System 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Chapter 3 53
3 Extent Attributes
Introduction
The VERITAS File System (VxFS) allocates disk space to files in groups of one or more adjacent blocks
called extents. VxFS defines an application interface that allows programs to control various aspects of the
extent allocation for a given file (see “Extent Information” on page 64). The extent allocation policies
associated with a file are referred to as extent attributes.
The VxFS getext(1M) and setext(1M) commands let you view or manipulate file extent attributes. In
addition, the vxdump, vxrestore, mv, cp, and cpio commands preserve extent attributes when a file is
backed up, moved, copied, or archived.
The following topics are covered in this chapter:
• Attribute Specifics
— Reservation: Preallocating Space to a File
— Fixed Extent Size
— Other Controls
• Commands Related to Extent Attributes
— Failure to Preserve Extent Attributes