HP-UX System Administrator's Guide: Overview

fstab(4)
The file /etc/fstab not only defines which file systems should
be mounted to which mount points in the directory tree (see “The
HP-UX Directory Structure” (page 44)), it is also one of the key
places you configure swap space.
lvlnboot(1M)
lvlnboot prepares an LVM logical volume to be root, boot,
primary swap, or a dump volume.
swapinfo(1M)
swapinfo prints information about device and file system paging
space.
swapon(1M)
The swapon command enables devices or file systems on which
paging is to take place.
swapoff(1M)
The swapoff command disables active paging areas, if possible.
The following kernel tunables affect paging activities on HP-UX:
nswapdev
Maximum number of swap devices that can be enabled for swap.
HP-UX Input and Output
Input and Output (I/O) on HP-UX is accomplished by reading from and writing to
special files known as device special files. Starting with HP-UX 11i version 3, there are
two types of device special files:
• Legacy Device Special Files
• Persistent Device Special Files
Persistent device special files offer many advantages over legacy device special files:
• With legacy device special files, if you move the device associated with them
(logically or physically) you will need to address those devices via new or different
device special files. This is because the device special files are associated with the
physical path to the device (the sequence of internal components that data must
travel). If any part of the path changes, a different device special file is needed.
• Persistent device special files are instead associated with a unique address on the
device (known as a worldwide identifier — WWID) rather than the path to the
device. This means that even if the path to the device changes, no changes are
needed to the device special files associated with that device.
Persistent device special files are only associated with mass storage devices.
Generally these are disk drives, some tape drives, and similar mass storage devices.
For non-mass storage devices, the traditional form of device special files (based
on hardware paths as with legacy device special files for mass storage devices)
still applies.
For more information on device special files, “How Storage is Addressed”.
HP-UX Input and Output 75