 | ||
| Expanded application facilities | ||
|---|---|---|
| Prev | Application program interface | Next |
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 VxFS-specific 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 VxFS-specific 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.