Veritas File System 5.0 Administrator's Guide (September 2006)

Application program interface
Veritas File System Developer's Kit (SDK) provides developers with the information
necessary to use the application programming interfaces (APIs) to modify and
tune various features and components of File System.
See the Veritas File System Programmer's Reference Guide.
VxFS conforms to the System V Interface Definition (SVID) requirements and
supports user access through the Network File System (NFS). Applications that
require performance features not available with other file systems can take
advantage of VxFS enhancements.
Expanded application facilities
VxFS provides API functions frequently associated with commercial applications
that make it possible to perform the following actions:
■ Preallocate space for a file
■ Specify a fixed extent size for a file
■ Bypass the system buffer cache for file I/O
■ Specify the expected access pattern for a file
Because these functions are provided using VxFS-specific ioctl system calls, most
existing UNIX system applications do not use them. The cp, cpio, and mv utilities
use the functions to preserve extent attributes and allocate space more efficiently.
The current attributes of a file can be listed using the getext or ls command. The
functions can also improve performance for custom applications. For portability
reasons, these applications must check which file system type they are using
before using these functions.
27Introducing Veritas File System
Using Veritas File System