HP-UX System Administrator's Guide: Overview

are not merely pointers indicating which file is in which directory; these are the low
level pointers and other vital information, for example:
• which disk blocks belong to which file
• which disk blocks are currently unused (so that specific disk blocks are not
simultaneously used for more than one purpose and order is maintained)
• linked lists of directory navigation information
File systems also have other important functions, for example maintaining ownership
and access privilege information so that HP-UX security functions can ensure that only
those authorized to access a file or directory can do so.
Supported File Systems
As with volume managers, HP-UX offers you several choices of file system types to
choose from. Specifically:
HFS The HP proprietary High-Performance File System supports files and file
system sizes up to 128GB.
VxFS The VERITAS File System Version 4.1 supports file sizes up to 16TB and file
system sizes up to 40TB. VxFS is also known as OnlineJFS/JFS 4.1.
In addition to the previous file system types, HP-UX 11i version 3 supports:
MEMFS This memory-based file system provides fast access to temporary files by
storing them in memory.
CDFS The CD file system allows you to read and write compact disc media using
ISSO-9660 format (either with or without the Rockridge Extensions).
The ISOIMAGE-ENH bundle provides support for mounting and unmounting
ISO Image files. This bundle is newly delivered in March, 2009 as an optional
product for all Operating Environments.
UDF The UDF file system is used for reading optical media written in the UDF
format. This allows you to read discs written by other operating systems that
support the UDF format.
FAT32 The 32-bit File Allocation Table file system is used primarily for boot and EFI
operations.
Efficient Data Access
If your operations depend on high performance disk I/O, in addition to ensuring that
you are using high-speed interfaces (for example, Fibre Channel), consider the following:
• Disk Striping
• Distributing Disk Access
• File System Type
• Establishing Multiple Paths to a Device (for efficiency)
• Disk Mirroring (for performance)
54 Major Components of HP-UX