VERITAS File System 4.1 Administrator's Guide

Extent Attributes
Commands Related to Extent Attributes
Chapter 3 73
Reservation Persistence
A reservation request can ensure that the reservation does not become a persistent attribute
of the file. The unused reservation is discarded when the file is closed.
Including Reservation in the File
A reservation request can make sure the size of the file is adjusted to include the reservation.
Normally, the space of the reservation is not included in the file until an extending write
operation requires it. A reservation that immediately changes the file size can generate large
temporary files. Unlike a ftruncate operation that increases the size of a file, this type of
reservation does not perform zeroing of the blocks included in the file and limits this facility to
users with appropriate privileges. The data that appears in the file may have been previously
contained in another file.
Commands Related to Extent Attributes
The VxFS commands for manipulating extent attributes are setext and getext; they allow
the user to set up files with a given set of extent attributes or view any attributes that are
already associated with a file. See the getext (1M) and setext (1M) manual pages for details on
using these commands.
The VxFS-specific commands vxdump and vxrestore, and the mv, cp, and cpio commands,
preserve extent attributes when backing up, restoring, moving, or copying files.
Most of these commands include a command line option (-e) for maintaining extent attributes
on files. This option specifies dealing with a VxFS file that has extent attribute information
including reserved space, a fixed extent size, and extent alignment. The extent attribute
information may be lost if the destination file system does not support extent attributes, has a
different block size than the source file system, or lacks free extents appropriate to satisfy the
extent attribute requirements.
The -e option takes any of the following keywords as an argument:
warn Issues a warning message if extent attribute information cannot
be maintained (the default)
force Fails the copy if extent attribute information cannot be
maintained
ignore Ignores extent attribute information entirely