Veritas File System 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

Veritas File System performance enhancements
Traditional file systems employ block-based allocation schemes that provide
adequate random access and latency for small files, but which limit throughput
for larger files. As a result, they are less than optimal for commercial
environments.
VxFS addresses this file system performance issue through an alternative
allocation method and increased user control over allocation, I/O, and caching
policies.
See “Using Veritas File System” on page 24.
VxFS provides the following performance enhancements:
■ Data synchronous I/O
■ Direct I/O and discovered direct I/O
■ Support for files and file systems up to 256 terabytes
■ Support for files up to 2 terabytes
■ Enhanced I/O performance
■ Caching advisories
■ Enhanced directory features
■ Explicit file alignment, extent size, and preallocation controls
■ Tunable I/O parameters
■ Tunable indirect data extent size
■ Integration with VxVM™
■ Support for large directories
Note: VxFS reduces the file lookup time in directories with an extremely large
number of files.
About enhanced I/O performance
VxFS provides enhanced I/O performance by applying an aggressive I/O clustering
policy, integrating with VxVM, and allowing application specific parameters to
be set on a per-file system basis.
23Introducing Veritas File System
Veritas File System performance enhancements