=============================
AIX: Paging space information
=============================
:Title:        AIX: Paging space information
:Author:       Douglas O'Leary <dkoleary@olearycomputers.com>
:Description:  How to get information on AIX paging space.
:Date created:
:Date updated:
:Disclaimer:   Standard: Use the information that follows at your own risk.  If you screw up a system, don't blame it on me...

AIX paging space concepts are the same as other systems. How to access that 
subsystem, though, is naturally different. Here's some information on the 
IBM/AIX paging subsystem.

.. contents::

Paging related commands:
========================

+---------+-------------------------------------------------+
| Command | Description                                     |
+=========+=================================================+
| chps    | Changes paging space attributes                 |
+---------+-------------------------------------------------+
| lsps    | Lists paging space attributegs                  |
+---------+-------------------------------------------------+
| mkps    | Creates paging space.                           |
+---------+-------------------------------------------------+
| rmps    | Remomves paging space (& lv on which it resies) |
+---------+-------------------------------------------------+
| swapon  | Activates paging                                |
+---------+-------------------------------------------------+

Deactivating paging space:
==========================

Like most modern UNIXes, AIX systems must be rebooted in order to fully 
deactivate paging space. The full process is as follows:

#. Unset the activation bit for the paging space in question::

      chps -a n ${lv}

#. Ensure the paging space that you are deactivating is not the default dump 
space. Update the default dump space to something else should that be the 
case::

      # sysdumpdev -l
      primary              /dev/dumplv
      secondary            /dev/sysdumpnull
      copy directory       /var/adm/ras
      forced copy flag     TRUE
      always allow dump    TRUE
      dump compression     OFF

      sysdumpdev -P -p ${new_dump_dev} # Sets the new dump device

#. Reboot.  ``shutdown -Fr now``

#. Confirm that the target paging space is no longer activated::

      # lsps -a
      Page Space  Physical Volume   Volume Group    Size   %Used  Active  Auto  Type
      paging00    hdisk3            rootvg        4096MB       1     yes   yes    lv
      hd6         hdisk2            rootvg        4096MB       1     yes   yes    lv

#. Remove the paging space and logical volume::

      rmps ${lv}

Modifying default paging space:
===============================

Anytime you're messing with the default paging space (other than increasing 
the size), you're going to have to supply a temporary default paging space. 
The checklist that follows shows all the steps required to reduce the size of 
the default paging lv, hd6.

#. Create a temporary paging space logical volume::

      mkps -a -n -s 30 rootvg ${disk}

#. Deactivate hd6 paging space:

      chps -a n hd6

#. Edit */sbin/rc.boot* to update the swapon command from hd6 to the name 
   output by the mkps command above (probably /dev/paging00).
#. Update, if necessary, the system dump device.

   a. Identify existing dump device by executing ``sysdumpdev -l``
   b. Update by executing ``sysdumpdev -P -p /dev/paging00``

#. Update the bootimage with the new paging/dump information by executing 
   ``bosboot -d /dev/hdisk0 -a``
#. Ensure the system key, if present, is in the normal position and reboot 
   the system.
#. After the sytem is up, ensure hd6 isn't being used by executing ``lsps -a``
#. Remove hd6 by executing ``rmps hd6``
#. Create a new hd by executing ``mklv -t paging -y hd6 rootvg 30``
#. Change the dump device back to hd6 by executing 
   ``sysdumpdev -P -p /dev/hd6``
#. Edit */sbin/rc.boot* to update the swapon command from the temporary to hd6.
#. Update the bootimage with the new paging/dump information by executing 
   ``bosboot -d /dev/hdisk0 -a``
#. Activate hd6 by executing ``chps -a y hd6``
#. Deactivate the temporary paging space by executing ``chps -a n paginng00``
#. Ensure the system key, if present, is in the normal position and reboot 
   the system.
#. When the system is back up, remove the temporary paging space by executing 
   ``rmps paging00``