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swap(1M)		System Administration Commands		      swap(1M)

NAME
       swap - swap administrative interface

SYNOPSIS
       /usr/sbin/swap -a swapname [swaplow] [swaplen]

       /usr/sbin/swap -d swapname [swaplow]

       /usr/sbin/swap -l

       /usr/sbin/swap -s

DESCRIPTION
       The  swap utility provides a method of adding, deleting,	and monitoring
       the system swap areas used by the memory	manager.

OPTIONS
       The following options are supported:

       -a swapname
	     Add the specified swap area. This option can only be used by  the
	     super-user.  swapname  is the name	of the swap file: for example,
	     /dev/dsk/c0t0d0s1 or a regular file. swaplow  is  the  offset  in
	     512-byte  blocks  into the	file where the swap area should	begin.
	     swaplen is	the desired  length  of	 the  swap  area  in  512-byte
	     blocks.  The  value of swaplen can	not be less than 16. For exam-
	     ple, if n blocks are specified, then (n-1)	blocks	would  be  the
	     actual  swap length. swaplen must be at least one page in length.
	     The size of a page	of memory can be determined by using the page-
	     size  command.  See  pagesize(1).	Since the first	page of	a swap
	     file is automatically skipped, and	a swap file  needs  to	be  at
	     least  one	 page in length, the minimum size should be a multiple
	     of	2 pagesize bytes. The size of a	page of	memory is machine  de-
	     pendent.

	     swaplow  +	 swaplen must be less than or equal to the size	of the
	     swap file.	If swaplen is not specified, an	 area  will  be	 added
	     starting  at  swaplow  and	extending to the end of	the designated
	     file. If neither swaplow nor swaplen  are	specified,  the	 whole
	     file  will	be used	except for the first page. Swap	areas are nor-
	     mally added automatically during system startup by	the /sbin/swa-
	     padd  script.  This  script  adds	all swap areas which have been
	     specified in the /etc/vfstab file;	for the	syntax of these	speci-
	     fications,	see vfstab(4).

	     To	 use  an  NFS  or local	file-system swapname, you should first
	     create a file using mkfile(1M). A local file-system swap file can
	     now  be  added  to	the running system by just running the swap -a
	     command. For NFS mounted swap files, the server needs  to	export
	     the file. Do this by performing the following steps:

	     1.	Add the	following line to /etc/dfs/dfstab:

		share  -F  nfs	-o rw=clientname,root=clientname path-to-swap-
		file

	     2.	Run shareall(1M).

	     3.	Have the client	add the	following lines	to /etc/vfstab:

		server:path-to-swap-file -  local-path-to-swap-filenfs --- lo-
		cal-path-to-swap-file -- swap ---

	     4.	Have the client	run mount:

		# mount	local-path-to-swap-file

	     5.	The client can then run	swap -a	to add the swap	space:

		# swap -a local-path-to-swap-file

       -d swapname
	     Delete  the  specified swap area. This option can only be used by
	     the super-user. swapname is the name of the swap file: for	 exam-
	     ple,  /dev/dsk/c0t0d0s1  or a regular file. swaplow is the	offset
	     in	512-byte blocks	into the swap area to be deleted.  If  swaplow
	     is	not specified, the area	will be	deleted	starting at the	second
	     page. When	the command completes, swap blocks can	no  longer  be
	     allocated from this area and all swap blocks previously in	use in
	     this swap area have been moved to other swap areas.

       -l    List the status of	all the	swap areas. The	output has  five  col-
	     umns:

	     path  The path name for the swap area.

	     dev   The	major/minor  device number in decimal if it is a block
		   special device; zeroes otherwise.

	     swaplo
		   The swaplow value for the area in 512-byte blocks.

	     blocks
		   The swaplen value for the area in 512-byte blocks.

	     free  The number of 512-byte blocks in this  area	that  are  not
		   currently allocated.

       The list	does not include swap space in the form	of physical memory be-
       cause this space	is not associated with a particular swap area.

	     If	swap -l	is run while swapname  is  in  the  process  of	 being
	     deleted  (by  swap	 -d),  the string INDEL	will appear in a sixth
	     column of the swap	stats.

       -s    Print summary information about total swap	space usage and	avail-
	     ability:

	     allocated
		   The total amount of swap space in bytes currently allocated
		   for use as backing store.

	     reserved
		   The total amount of swap space in bytes not currently allo-
		   cated,  but	claimed	by memory mappings for possible	future
		   use.

	     used  The total amount of swap space in bytes that	is either  al-
		   located or reserved.

	     available
		   The	total  swap space in bytes that	is currently available
		   for future reservation and allocation.

	     These numbers include swap	space from all configured  swap	 areas
	     as	 listed	 by  the  -l option, as	well swap space	in the form of
	     physical memory.

USAGE
       Only the	first 2	Gbyte of a block device	larger than 2  Gbyte  in  size
       can  be	used  for  swap	in swapfs on a 32-bit operating	system.	With a
       64-bit operating	system,	a block	device larger  than  2	Gbyte  can  be
       fully utilized for swap up to 2**63 -1 bytes.

ENVIRONMENT VARIABLES
       See  environ(5) for descriptions	of the following environment variables
       that affect the execution of swap: LC_CTYPE and LC_MESSAGE.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       pagesize(1), mkfile(1M),	shareall(1M), getpagesize(3C), vfstab(4),  at-
       tributes(5), largefile(5)

WARNINGS
       No  check is done to determine if a swap	area being added overlaps with
       an existing file	system.

SunOS 5.9			  11 Jul 2001			      swap(1M)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | USAGE | ENVIRONMENT VARIABLES | ATTRIBUTES | SEE ALSO | WARNINGS

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