HP-UX Reference (11i v2 03/08) - 1M System Administration Commands N-Z (vol 4)

s
swapinfo(1M) swapinfo(1M)
NAME
swapinfo - system paging space information
SYNOPSIS
/usr/sbin/swapinfo
[-mtadfnrMqw]
DESCRIPTION
swapinfo prints information about device and file system paging space. (Note: the term ‘swap’ refers to
an obsolete implementation of virtual memory;
HP-UX actually implements virtual memory by way of pag-
ing rather than swapping. This command and others retain names derived from ‘swap’ for historical rea-
sons.)
By default,
swapinfo prints to standard output a two line header as shown here, followed by one line
per paging area:
Kb Kb Kb PCT START/ Kb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
The fields are:
TYPE One of:
dev Paging space residing on a mass storage device, either taking up the entire dev-
ice or, if the device contains a file system, taking up the space between the end
of the file system and the end of the device. This space is exclusively reserved
for paging, and even if it is not being used for paging, it cannot be used for any
other purpose. Device paging areas typically provide the fastest paging.
fs Dynamic paging space available from a file system. When this space is needed,
the system creates files in the file system and uses them as paging space. File
system paging is typically slower than device paging, but allows the space to be
used for other things (user files) when not needed for paging.
localfs File system paging space (see fs above) on a file system residing on a local disk.
network File system paging space (see fs above) on a file system residing on another
machine. This file system would have been mounted on the local machine via
NFS.
reserve Paging space on reserve. This is the amount of paging space that could be
needed by processes that are currently running, but that has not yet been allo-
cated from one of the above paging areas. See "Paging Allocation" below.
memory Memory paging area (also known as pseudo-swap). This is the amount of system
memory that can be used to hold pages in the event that all of the above paging
areas are used up. See "Paging Allocation" below. This line appears only if
memory paging is enabled.
Kb AVAIL The total available space from the paging area, in blocks of 1024 bytes (rounded to nearest
whole block if necessary), including any paging space already in use.
For file system paging areas the value is not necessarily constant. It is the current space
allocated for paging (even if not currently used), plus the free blocks available on the file sys-
tem to ordinary users, minus RESERVE (but never less than zero). AVAIL is never more
than LIMIT if LIMIT is non-zero. Since paging space is allocated in large chunks, AVAIL is
rounded down to the nearest full allocation chunk.
For the memory paging area this value is also not necessarily constant, because it reflects
allocation of memory by the kernel as well as by processes that might need to be paged.
Kb USED The current number of 1-Kbyte blocks used for paging in the paging area. For the memory
paging area, this count also includes memory used for other purposes and thus unavailable
for paging.
Kb FREE The amount of space that can be used for future paging. Usually this is the difference
between Kb AVAIL and Kb USED. There could be a difference if some portion of a device
paging area is unusable, perhaps because the size of the paging area is not a multiple of the
allocation chunk size, or because the tunable parameter swchunk is not set high enough.
Section 1M−−788 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: August 2003