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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  example,
		       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 de-
		       termined	by  using  the	pagesize  command.  See	 page-
		       size(1).	 Since	the first page of a swap file is auto-
		       matically skipped, and a	swap file needs	to be at least
		       one page	in length, the minimum size should be a	multi-
		       ple of 2	pagesize bytes.	The size of a page  of	memory
		       is machine dependent.

		       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 ex-
		       cept for	the first page.	Swap areas are normally	 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	specifications,	see vfstab(4).

		       To use an NFS or	local file-system swapname, you	should
		       first create a file using mkfile(1M). A local file-sys-
		       tem 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  line to
			       /etc/vfstab:

			       server:path-to-swap-file	-  local-path-to-swap-filenfs \
				    ---	local-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 example,	/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	previ-
		       ously 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 columns:

		       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 because 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  ap-
		       pear in a sixth column of the swap stats.

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

		       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 allocated,	but claimed by
				       memory  mappings	 for  possible	future
				       use.

		       used	       The total amount	of swap	space in bytes
				       that is either allocated	or reserved.

		       available       The total swap space in bytes  that  is
				       currently available for future reserva-
				       tion 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
       On the 32-bit operating system, only the	first 2	Gbytes -1 are used for
       swap  devices  greater than or equal to 2 Gbytes	in size. On the	64-bit
       operating system, a block device	larger than 2 Gbytes can be fully uti-
       lized 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 5.10			  20 Jan 2004			      swap(1M)

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

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