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 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
      paging rather than swapping.  This command and others retain names
      derived from `swap' for historical reasons.)

      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 device 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



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 swapinfo(1M)							swapinfo(1M)




			     that are currently running, but that has not
			     yet been allocated 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 system 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 maxswapchunks
		  is not set high enough.

      PCT USED	  The percentage of capacity in use, based on Kb USED
		  divided by Kb AVAIL; 100% if Kb AVAIL is zero.

      START/LIMIT For device paging areas, START is the block address on the
		  mass storage device of the start of the paging area.	The
		  value is normally 0 for devices dedicated to paging, or
		  the end of the file system for devices containing both a
		  file system and paging space.




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 swapinfo(1M)							swapinfo(1M)




		  For file system paging areas, LIMIT is the maximum number
		  of 1-Kbyte blocks that will be used for paging, the same
		  as the limit value given to swapon.  A file system LIMIT
		  value of none means there is no fixed limit; all space is
		  available except that used for files, less the blocks
		  represented by minfree (see fs(4)) plus RESERVE.

      RESERVE	  For device paging areas, this value is always ``-''.	For
		  file system paging areas, this value is the number of 1-
		  Kbyte blocks reserved for file system use by ordinary
		  users, the same as the reserve value given to swapon.

      PRI	  The same as the priority value given to swapon.  This
		  value indicates the order in which space is taken from the
		  devices and file systems used for paging.  Space is taken
		  from areas with lower priority values first.	priority can
		  have a value between 0 and 10.  See "Paging Allocation"
		  below.

      NAME	  For device paging areas, the block special file name whose
		  major and minor numbers match the device's ID.  The
		  swapinfo command searches the /dev tree to find device
		  names.  If no matching block special file is found,
		  swapinfo prints the device ID (major and minor values),
		  for example, 28,0x15000.

		  For file system swap areas, NAME is the name of a
		  directory on the file system in which the paging files are
		  stored.

    Paging Allocation
      Paging areas are enabled at boot time (for device paging areas
      configured into the kernel) or by the swapon command (see swapon(1M)),
      often invoked by /sbin/init.d/swap_start during system initialization
      based on the contents of /etc/fstab.  When a paging area is enabled,
      some portion of that area is allocated for paging space.	For device
      paging areas, the entire device is allocated, less any leftover
      fraction of an allocation chunk.	(The size of an allocation chunk is
      controlled by the tunable parameter swchunk, and is typically 2 MB.)
      For file system paging areas, the minimum value given to swapon
      (rounded up to the nearest allocation chunk) is allocated.

      When a process is created, or requests additional space, space is
      reserved for it by increasing the space shown on the reserve line
      above.  When paging activity actually occurs, space is used in one of
      the paging areas (the one with the lowest priority number that has
      free space available, already allocated), and that space will be shown
      as used in that area.

      The sum of the space used in all of the paging areas, plus the amount
      of space reserved, can never exceed the total amount allocated in all



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 swapinfo(1M)							swapinfo(1M)




      of the paging areas.  If a request for more memory occurs which would
      cause this to happen, the system tries several options:

      1.   The system tries to increase the total space available by
	   allocating more space in file system paging areas.

      2.   If all file system paging areas are completely allocated and the
	   request is still not satisfied, the system will try to use memory
	   paging as described on the memory line above.  (Memory paging is
	   controlled by the tunable parameter swapmem_on, which defaults to
	   1 (on).  If this parameter is turned off, the memory line will
	   not appear.)

      3.   If memory paging also cannot satisfy the request, because it is
	   full or turned off, the request is denied.

      Several implications of this procedure are noteworthy for
      understanding the output of swapinfo:

      +	   Paging space will not be allocated in a file system paging area
	   (except for the minimum specified when the area is first enabled)
	   until all device paging space has been reserved, even if the file
	   system paging area has a lower priority value.

      +	   When paging space is allocated to a file system paging area, that
	   space becomes unavailable for user files, even if there is no
	   paging activity to it.

      +	   Requests for more paging space will fail when they cannot be
	   satisfied by reserving device, file system, or memory paging,
	   even if some of the reserved paging space is not yet in use.
	   Thus it is possible for requests for more paging space to be
	   denied when some, or even all, of the paging areas show zero
	   usage - space in those areas is completely reserved.

      +	   System available memory is shared between the paging subsystem
	   and kernel memory allocators.  Thus, the system may show memory
	   paging usage before all available disk paging space is completely
	   reserved or fully allocated.

    Logical Volume Manager (LVM)
      The swapinfo command displays swap logical volume if the system was
      installed with LVM.  To modify swap logical volume, refer to the LVM
      commands and manpages for lvlnboot and lvrmboot.	For example, to
      remove a swap logical volume, run the following LVM command:

	   lvrmboot -s

    Options
      swapinfo recognizes the following options:




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 swapinfo(1M)							swapinfo(1M)




	   -m	Display the AVAIL, USED, FREE, LIMIT, and RESERVE values in
		Mbytes instead of Kbytes, rounding off to the nearest whole
		Mbyte (multiples of 1024^2).  The output header format
		changes from Kb to Mb accordingly.

	   -t	Add a totals line with a TYPE of total.	 This line totals
		only the paging information displayed above it, not all
		paging areas; this line might be misleading if a subset of
		-dfrM is specified.

	   -a	Show all device paging areas, including those configured
		into the kernel but currently disabled.	 (These are normally
		omitted.) The word disabled appears after the NAME, and the
		Kb AVAIL, Kb USED, and Kb FREE values are 0.  The -a option
		is ignored unless the -d option is present or is true by
		default.

	   -d	Print information about device paging areas only.  This
		modifies the output header appropriately.

	   -f	Print information about file system paging areas only.	This
		modifies the output header appropriately.

	   -n	Categorize file system paging area information into localfs
		areas and network areas, instead of calling them both fs
		areas.

	   -r	Print information about reserved paging space only.

	   -M	Print information about memory paging space only.

		The -d, -f, -n, -r and -M options can be combined.  The
		default is -dfnrM.

	   -q	Quiet mode.  Print only a total "Kb AVAIL" value (with the
		-m option, Mb AVAIL); that is, the total paging space
		available on the system (device, file system, reserve, or
		memory paging space only if -d, -f, -r, or -M is specified),
		for possible use by programs that want a quick total.  If -q
		is specified, the -t and -a options are ignored.

	   -w	Print a warning about each device paging area that contains
		wasted space; that is, any device paging area whose
		allocated size is less than its total size.  This option is
		effective only if -d is also specified or true by default.

 RETURN VALUE
      swapinfo returns 0 if it completes successfully (including if any
      warnings are issued), or 1 if it reports any errors.





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 swapinfo(1M)							swapinfo(1M)




 DIAGNOSTICS
      swapinfo prints messages to standard error if it has any problems.

 EXAMPLES
      List all file system paging areas with a totals line:

	   swapinfo -ft

 WARNINGS
      swapinfo needs kernel access for some information.  If the user does
      not have appropriate privileges for kernel access, swapinfo will print
      a warning and assume that the defaults for that information have not
      been changed.

      Users of swapinfo must not rely on the exact field widths and spacing
      of its output, as these will vary depending on the system, the release
      of HP-UX, and the data to be displayed.

      The information in this manual page about paging allocation and other
      implementation details may change without warning; users should not
      rely on the accuracy of this information.

 AUTHOR
      swapinfo was developed by HP.

 SEE ALSO
      lvlnboot(1M), lvrmboot(1M), swapon(1M), swapon(2), fstab(4), fs(4).



























 Hewlett-Packard Company	    - 6 -   HP-UX Release 11i: November 2000