HP JFS 3.3 and HP OnLineJFS 3.3 VERITAS File System 3.3 System Administrator's Guide

110 Chapter6
Application Interface
Introduction
Introduction
The VxFS File System provides enhancements that can be used by
applications that require certain performance features. This chapter
describes cache advisories and provides information about fixed extent
sizes and reservation of space for a file.
This chapter describes how the application writer can optimize
applications for use with the VxFS. To optimize VxFS for use with
applications, see Chapter 5 , “Performance and Tuning.”
The following topics are covered in this chapter:
• “Cache Advisories”
— “Direct I/O”
— “Unbuffered I/O”
— “Discovered Direct I/O”
— “Data Synchronous I/O”
— “Other Advisories”
• “Extent Information”
— “Space Reservation”
— “Fixed Extent Sizes”
— “Freeze and Thaw”
• “Get I/O Parameters ioctl”