myaix

HOWTO INSTALL OPEN SSH ON AIX6.1

2011-02-18T01:27:00.000-08:00

1. To install open ssh you will also need open ssl.

for open ssl you can download from:
https://www14.software.ibm.com/webapp/iwm/web/reg/download.do?source=aixbp&S_PKG=openssl&lang=en_US&cp=UTF-8

the file name is:
openssl.0.9.8.1301.tar.Z (6 MB)

for open ssh you can download from:
http://sourceforge.net/projects/openssh-aix/files/openssh-aix%20Source%20Patch/Openssh-4.5p1_srcpatch/openssh-4.5_srcpatch.tar/download

the file name:
openssh-4.5_srcpatch.tar

2. Once downloaded create a directory (eg /tmp/openssh) and transfer the files.
3. uncompress the files
4. tar -xvf for openssl and openssh

tar -xvf ./openssl.0.9.8.1301.tar
tar -xvf ./openssh-4.5_srcpatch.tar

5. install the openssl first. when you tar the open ssl file, it will create an openssl directory. cd to that directory. run this command
/tmp/openssh> cd openssl.0.9.8.1301
/tmp/openssh/openssl0.9.8.1301> inutoc .

use smit install and point the installation directory to /tmp/openssh/openssl0.9.8.1301 . remember to choose accept new licence as yes and all the files need to install.

6. the install openssh.
/tmp/openssh> inutoc .

use smit install and point the installation directory to /tmp/openssh . Remember to choose accept new license as yes and all the files need to install

7. to start the ssh , run the daemon as root user

/tmp/openssh> startsrc -g sshd

Good luck!

AIX IN THE UNIX WORLD

2011-01-21T18:09:00.000-08:00

Twenty five years ago on January 21, 1986, IBM Austin launched a new operating system called IBM RT Personal Computer Advanced Interactive eXecutive -- better known as AIX -- with a new system called the IBM RT PC. The system ran on a RISC processor codenamed “ROMP” (for Research Office Products Division MultiProcessor) and was originally marketed as an engineering workstation.

This new AIX operating system was based on UNIX operating system, but it included significant IBM enhancements such as a virtualization to allow multiple operating systems to run on a single machine, support for high resolution displays, and a simple user interface.

Over the ensuing years we have seen significant advances in the evolution of AIX:
- 1990, AIX V3 on the RS/6000 on the first POWER processor
- 1994, AIX V4 with support for symmetric multiprocessing
- 2001, AIX 5L provides logical partitioning virtualization on POWER4
- 2007, AIX 6 contains workload partitions
- 2010, AIX 7 has built in clustering and the ability to host an earlier version of AIX

Of course AIX was not evolving alone – since that original release on the RT PC in 1986, the capabilities of Power processor and hardware grew from a single processor running at 5.9 MHz to today’s Power 795 running up to 256 POWER7 cores at 4.25 GHz..

Throughout this evolution, the AIX and Power Systems market position has grown from a small fraction of the engineering workstation market to the market leader of the $16 billion enterprise UNIX server market. Leadership performance has long been key part of this success, but AIX and Power Systems also lead the market in reliability and availability.

AIX QUICK SHEET

2010-03-29T02:11:00.000-07:00

Filesystems

/dev/hd1 /home
/dev/hd2 /usr
/dev/hd3 /tmp
/dev/hd4 / root
/dev/hd5 BLV (Boot Logical Volume)
/dev/hd6 Paging space
/dev/hd8 JFS2 log
/dev/hd9var /var
/dev/hd10opt /opt
/dev/hd11admin /admin New in 6.1
livedump /var/adm/ras/livedump New in 6.1 TL3
/proc procfs pseudo filesystem
Remove mount point entry and the LV for /mymount
rmfs /mymount (Add -r to remove mount point)

Grow the /var lesystem by 1 Gig
chfs -a size=+1G /var

Grow the /var lesystem to 1 Gig
chfs -a size=1G /var

Find the file usage on a fi lesystem
du -smx /

List filesystems in a grep-able format
lsfs

Get extended information about the /home filesystem
lsfs -q /home

Create a log device on datavg VG
mklv -t jfs2log -y datalog1 datavg 1

Format the log device just created
logform /dev/datalog1

Kernel Tuning

- no is used in the following examples. vmo, no, nfso, ioo, raso, and schedo all use similar syntax. lvmo uses di fferent syntax.

Reset all networking tunable to the default values
no -D (Changed values will be listed)

List all networking tunable
no -a

Set a tunable temporarily (until reboot)
no -o use isno=1

Set a tunable at next reboot
no -r -o use isno=1

Set current value of tunable as well as reboot
no -p -o use isno=1

List all settings, defaults, min, max, and next boot values
no -L

List all sys0 tunables
lsattr -El sys0

Get information on the minperm% vmo tunable
vmo -h minperm%

Change the maximum number of user processes to 2048
chdev -l sys0 -a maxuproc=2048

Check to see if SMT is enabled
smtctl

Directory containing tunables settings
/etc/tunables/

ODM
Query CuDv for a specific item
odmget -q name=hdisk0 CuDv

Query CuDv using the \like" syntax
odmget -q "name like hdisk?" CuDv

Query CuDv using a complex query
odmget -q "name like hdisk? and parent like vscsi?" CuDv

Devices
List all devices on a system
lsdev

List all disk devices on a system (See next item for a list of classes)
lsdev -Cc disk

List all customized (existing) device classes (-P for complete list)
lsdev -C -r class

Remove hdisk5
rmdev -dl hdisk5

Get device address of hdisk1
getconf DISK DEVNAME hdisk1 (or) bootinfo -o hdisk1

Get the size (in MB) of hdisk1
getconf DISK SIZE /dev/hdisk1 (or) bootinfo -s hdisk1

List all disks belonging to scsi0
lsdev -Cc disk -p scsi0

Find the slot of a PCI Ethernet adapter
lsslot -c pci -l ent0

Find the (virtual) location of an Ethernet adapter
lscfg -l ent1

Find the location codes of all devices in the system
lscfg

List all MPIO paths for hdisk0
lspath -l hdisk0

Find the WWN of the fcs0 HBA adapter
lscfg -vl fcs0 | grep Network

Temporarily change console output to /console.out
swcons /console.out -> (Use swcons to change back.)

Get statistics and extended information on fcs0
fcstat fcs0

Tasks
Change port type of HBA (This may vary by HBA vendor)
rmdev -d -l fcnet0
rmdev -d -l fscsi0
chdev -l fcs0 -a link type=pt2pt
cfgmgr

Mirroring rootvg to hdisk1
extendvg rootvg hdisk1
mirrorvg rootvg
bosboot -ad hdisk0
bosboot -ad hdisk1
bootlist -m normal hdisk0 hdisk1

Mount a CD/DVD ROM to /mnt

mount -rv cdrfs /dev/cd0 /mnt -> (for a CD)
mount -v udfs -o ro /dev/cd0 /mnt -> (for a DVD)
-> Note the two di erent types of read-only flags. Either is Ok.

Create a VG, LV, and FS, mirror, and create mirrored LV

mkvg -s 256 -y datavg hdisk1 (PP size is 1/4 Gig)
mklv -t jfs2log -y dataloglv datavg 1
logform /dev/dataloglv
mklv -t jfs2 -y data01lv datavg 8 -> (2 Gig LV)
crfs -v jfs2 -d data01lv -m /data01 -A yes
extendvg datavg hdisk2
mklvcopy dataloglv 2 -> (Note use of mirrorvg in next example)
mklvcopy data01lv 2
syncvg -v datavg
lsvg -l datavg will now list 2 PPs for every LP
mklv -c 2 -t jfs2 -y data02lv datavg 8 -> (2 Gig LV)
crfs -v jfs2 -d data02lv -m /data02 -A yes
mount -a

Move a VG from hdisk1 to hdisk2

extendvg datavg hdisk2
mirrorvg datavg hdisk2
-> Wait for mirrors to synchronize
unmirrorvg datavg hdisk1
reducevg datavg hdisk1

Find the free space on PV hdisk1
lspv hdisk1 ! (Look for \FREE PPs")

Additional Information
http://publib.boulder.ibm.com/infocenter/systems/scope/aix
http://www.redbooks.ibm.com/portals/unix
Display error codes can be found in the \Diagnostic Information for Multiple Bus Systems" manual

About this QuickSheet
Created by: William Favorite (wfavorite@tablespace.net)
Updates at: http://www.tablespace.net/quicksheet/
Disclaimer: This document is a guide and it includes no express warranties to the suitability, relevance, or compatibility of its contents with any specfi c system. Research any and all commands that you inflict upon your command line.
Distribution: The PDF version is free to redistribute as long as credit to the author and tablespace.net is retained in the printed and viewable versions. LATEX source not distributed at this time.

New and Update IBM Redbooks

2009-08-15T03:14:00.000-07:00

TS7650G and TS7650 ProtecTIER De-duplication Servers

Revised: August 7, 2009

http://w3.itso.ibm.com/redpieces/abstracts/sg247652.html?Open

Tuning System x Servers for Performance

Published: August 4, 2009 ISBN: 0738433071 848 pages

http://www.redbooks.ibm.com/abstracts/sg245287.html?Open

Implementing an iDataPlex Solution

Published: August 4, 2009 ISBN: 0738433233 272 pages

http://www.redbooks.ibm.com/abstracts/sg247629.html?Open

Managing Unified Storage with N-Series Operation Manager

Published: August 4, 2009 ISBN: 0738433160 576 pages

http://www.redbooks.ibm.com/abstracts/sg247734.html?Open

PowerVM Virtualization on System p: Intro & Configuration

Revised: July 29, 2009 ISBN: 0738485306 398 pages

http://www.redbooks.ibm.com/abstracts/sg247940.html?Open

Power 520 Technical Overview

Revised: July 29, 2009

http://www.redbooks.ibm.com/redpapers/abstracts/redp4403.html?Open

Brocade 8Gb FC Single-port and Dual-port HBA for System x

Published: July 31, 2009

http://www.redbooks.ibm.com/abstracts/tips0719.html?Open

QLogic 8Gb FC Single-port and Dual-port HBAs for System x

Published: July 31, 2009

http://www.redbooks.ibm.com/abstracts/tips0721.html?Open

System hang after update to 6100-03

2009-08-15T03:12:00.000-07:00

Systems with Encypted File System (EFS) support enabled may fail to boot after updating to the 6100-03 Technology Level.

This problem occurs if the clic.rte.kernext and clic.rte.lib filesets are installed at a

level below 4.6.0.0. EFS may be enabled if the 'efsenable' command was ever executed

on the system, even if there are no encrypted file systems currently in use. The presence of the file /var/efs/efsenabled indicates that EFS is enabled.

To avoid this issue, update the clic.rte.kernext and clic.rte.lib filesets to the 4.6.0.0 level from the clic.rte image available on the AIX Expansion Pack, dated 5/2009 or later. The clic.rte filesets need to be updated before the system is rebooted after updating to the 6100-03 Technology Level.

If the 6100-03 Technology Level is installed without updating the clic.rte filesets to the 4.6.0.0 level, the system may fail to reboot. Should this occur, you can recover using the following procedure.

1. Reboot system into service mode

2. Select 'Task Selection', then chose 'Shell Prompt'

3. Move file /var/efs/efsenabled to /var/efs/efsenabled.SAVE

4. Reboot system into normal mode

5. Update clic.rte.kernext and clic.rte.lib to the 4.6.0.0 level

6. Move back /var/efs/efsenabled from /var/efs/efsenabled.SAVE

Distribution of the 6100-03 Technology Level on Fix Central has been temporarily suspended until this issue is resolved.

So, be warned!

changing 32bit kernel to 64bit kernel

2009-07-24T05:05:00.000-07:00

how would you change a 32bit kernel to 64bit. In aix5L the procedures are:

1. smitty load64bit

This will take you to the following menu :

Enable Now
Enable/Disable at System Restart

2. Select enable now and then select enable 64 bit env. at system restart.
3. A line is added to inittab to load this automatically at system reboot.

If you are not sure, try this command:

To switch from 32-bit mode to 64-bit mode run the following commands, in the given order:

1. ln -sf /usr/lib/boot/unix_64 /unix
2. ln -sf /usr/lib/boot/unix_64 /usr/lib/boot/unix
3. bosboot -ad /dev/ipldevice
4. shutdown -Fr
5. bootinfo -K (should now show 64)

To switch from 64-bit mode to 32-bit mode run the following commands, in the given order:

1. ln -sf /usr/lib/boot/unix_mp /unix
2. ln -sf /usr/lib/boot/unix_mp /usr/lib/boot/unix
3. bosboot -ad /dev/ipldevice
4. shutdown -Fr
5. bootinfo -K (should now show 32)

Now, the biggest question would be, whu 64bit?

The advantages of a 64 bit kernel in memory addressing, maximum file size, maximum partition size, in the LVM if you use it and of course it faster.

FYI .In AIX4.3 the kernel is only 32-bit.

pwc2id5hr3

2009-07-20T22:29:00.001-07:00

IBM Power servers most reliable in new survey

2009-07-16T19:09:00.000-07:00

Windows Server machines most improved, but still suffer high downtime By Jon Brodkin , Network World , 07/14/2009

IBM's Power servers topped a list of most reliable x86 and Unix machines in a new survey, clocking in at only 15 minutes of unplanned downtime peryear.

Linux distributions running on x86 servers also performed well, as did Sun's Sparc machines and

HP's Unix boxes. Windows Server machines performed worse than most competitors, with two

to three hours of downtime per year, but have still improved dramatically over previous surveys.

"Ten to 15 years ago, there was a lot more downtime [for all types of servers]," says Laura

DiDio, lead analyst with Information Technology Intelligence. "Both the hardware and operating

system software has gotten much better."

ITIC picked 15 of the most popular server hardware and operating system combinations, and polled Clevel executives and IT managers at 400 organizations across 20 countries about unplanned downtime, patching and other indicators of reliability.

IBM's Power servers with the AIX Unix operating system suffered an average of 15 minutes of

unplanned downtime per year in the most recent survey, down from 30 minutes in the 2008 survey. IBM also came in first place for average time to patch a server (11 minutes per patch) and for lowest number of outages per year.

"For the second year in a row, IBM AIX UNIX running on the Power or "P" series servers, scored the highest reliability ratings among 15 different server operating system platforms -- including Linux, Mac OS X, UNIX and Windows," DiDio writes in a blog post. The second most reliable servers in terms of downtime were customized versions of Novell SuSE Linux

running on standard x86 hardware, clocking in at 17.4 minutes of downtime per year. Un-customized Novell SuSE Linux machines had 54 minutes of downtime.

Linux distributions such as TurboLinux and Mandriva on standard x86 hardware suffered 31.8 minutes of downtime a year, while Sun Solaris on Sparc servers suffered 35.4 minutes downtime a year. HP 9000 servers running HP's Unix operating system came in fifth place with 36 minutes of downtime per year, while HP also took seventh place with Integrity servers (39 minutes downtime).

Apple's G4 Mac servers with the Mac OS X operating system came in sixth with 37.8 minutes

downtime. "The survey respondents indicated that Apple products are extremely competitive in an enterprise setting," DiDio writes.

The worst performers were open source Linux distributions such as Debian, with more than four hours unplanned downtime per year. The next-worst were Windows Server 2003 on Intel-based hardware (three hours of downtime) and Windows Server 2008 (nearly two and a half hours downtime). But Windows Server systems also posted the biggest improvement, with a 35% reduction in downtime since2008.

Ubuntu-based servers seemed to go backwards, from one hour of downtime in 2008 to one hour, 41 minutes in 2009. That is more a function of the type of user attracted to Ubuntu, however, DiDio says. "Ubuntu is very leading edge. Ubuntu users do a lot of experimentation" and can thus expect some downtime, she says. DiDio attempted to measure reliability of most popular enterprise servers, she decided not to include mainframes, which probably would have taken the top spot.

"Mainframes are in a class by themselves," DiDio notes. "Whatever you say, you're not taking the mainframe down. It's like the Rock of Gibraltar."

This story appeared on Network World at

http://www.networkworld.com/news/2009/071409-ibm-power-servers.html

IBM REDBOOKS JULY RELEASED

2009-07-15T04:33:00.001-07:00

PowerHA for AIX Cookbook

Revised: July 6, 2009

http://www.redbooks.ibm.com/redpieces/abstracts/sg247739.html?Open

p6-520 & p6-550 System Builder

Revised: July 7, 2009

http://www.redbooks.ibm.com/redpieces/abstracts/sg247765.html?Open

PowerVM: Intro & Configuration

Revised: July 10, 2009 ISBN: 0738485306 394 pages

http://www.redbooks.ibm.com/abstracts/sg247940.html?Open

High Availability Solution for IBM FileNet P8

Revised: July 7, 2009

http://www.redbooks.ibm.com/redpieces/abstracts/sg247700.html?Open

ServeRAID Adapter Quick Reference

Revised: July 7, 2009

http://www.redbooks.ibm.com/abstracts/tips0054.html?Open

Brocade 10Gb CNA for IBM System x

Revised: July 6, 2009

http://www.redbooks.ibm.com/abstracts/tips0718.html?Open

QUOTE: he who knows all knows nothing

TSM commands (quickie)

2009-07-02T18:01:00.000-07:00

Some commands gathered during my stint as a tsm administrator. a very short stint. Anyways assumptions are:
library name is 3494lib.
physical tape media is B00001
for finer details just add f=d at the end of the commands. e.g. q mount f=d..
not all commands works and be careful when executing especially when updating status of private to scratch.

1. to update tape in private status to scratch status
tsm: ADSM> update libvol 3494lib B00001 status=scr

2. to check status of tape last written/read
tsm: ADSM> q vol B00001 f=d

3. to check the content of tape
tsm: ADSM> q con B00001

4. check which tape is mounted for during operation
tsm: ADSM> q mount

5. to check whether the session of tsm has started
tsm: ADSM> q session

6. to check the sotrage pool operation
tsm: ADSM> q vol * stgpool=3494lib

7. to erase the content of data on tape and turn it to scratch
tsm: ADSM> del vol B00001 discarddata=yes

8. To update the path to drive1:
TSM>upd path ADSM 3590DRIVE1 srct=server destt=drive online=yes libr=3494lib autod=yes

9.To check the volume mounted:
TSM>q mount

10. to update the path
tsm: ADSM>update drive 3494lib 3590drive3 online=yes

11. to check the activity log from 3 days ago until today
tsm: ADSM>q actlog begind=today-3

12 to check status of path in finer details
tsm: ADSM>q path f=d

13. to check schedule of works in TSM
tsm: ADSM> q sched t=a

HACMP commands

2009-07-02T04:34:00.000-07:00

Sometime i forgot certain commands when trying to figure out HACMP stuffs. So i look through Mr Google and find some that i think might be useful. Will add some more.

clstat - shows cluster state

cldump - SNMP-based tool to show cluster state

cldisp - perl script to show cluster state

cltopinfo - list local view of cluster topology

clvt -

clshowsrv - local view of cluster subsystem

clfindres, clRGinfo - locate resource groups for displaying status

clcycle -

cl_ping - cluster style pinging

clgetactivenodes - show nodes that are active

get_local_nodename - get local node name

clconfig

cldare - syncro cluster, be careful using this command

cllsgrp - list the resource group

cllscf - list network config of a cluster

clshowres -

cllsif - lists network interface information

cllsres - lists resource group info

lssrc -ls topsvcs - hearbeat info

lssrc -ls clstrmgrES - lists cluster manager internal state

clver -Nv -

clharvest_vg -w -

notice that some commands have no explaination. I haven't tested the command and therefore wouldn't know the effect. Try it yourself. Never know,eh? Just be careful. Somebody told me to never forgets to do system backup or 'mksysb' before testing and doing stuffs on AIX.

IBM REDBOOKS JUNE RELEASED

2009-06-27T02:06:00.000-07:00

PowerVM Virtualization Active Memory Sharing

Revised: June 19, 2009

http://www.redbooks.ibm.com/redpapers/abstracts/redp4470.html?Open

DS8000 Disk Encryption Implementation & Usage Guidelines

Revised: June 15, 2009

http://www.redbooks.ibm.com/redpapers/abstracts/redp4500.html?Open

N-Series Operation & Protection Manager to Manage Your Unified Storage Environment

Published: June 19, 2009

http://w3.itso.ibm.com/redpieces/abstracts/sg247734.html?Open

Brocade 10Gb CNA for IBM System-x

Published: June 16, 2009

http://www.redbooks.ibm.com/abstracts/tips0718.html?Open

QLogic 10Gb CNA for IBM System-x

Published: June 16, 2009

http://www.redbooks.ibm.com/abstracts/tips0720.html?Open

Frequent Print Error Messages

2009-06-22T05:24:00.000-07:00

My friend called me this evening asking me to help with her problem regarding adding print queue.. Error 0781-017 . As i was driving, i can only help her once i stop driving and reached office. In the meantime, she told me she use google and manage to find the answer. She was nice enough to give the link to me.

http://www-01.ibm.com/support/docview.wss?uid=isg3T1000284

Problem
Frequent Print Error Messages

Solution

This document describes some of the more common printing error messages, and outlines some solutions to resolve these problems. This document applies to AIX Version 4.3 and later.

Hey, i got some interesting link that you people wanna try.

www.postful.com - send an email and turn to physical mail. Design post card on line and send it in physical postcard. Cool. www.jott.com - call a simple phone number, speak your notes, messages, or updates and hang up. Jott Voicemail works the same way, but your friends, family, and colleagues are the ones leaving the messages when they call your number. Then, Jott takes the spoken messages, turns them into text, and sends them to the right destination via email, text message, or web update. www.telegram.com - hey, i won't give it all to you, eh? Try it and found out what it's all about.

IBM REDBOOKS MAY RELEASED

2009-06-17T16:49:00.000-07:00

somebody pass me this info. Once in a while ibm will publish redbooks also known as technical guide or manuals or cookbook. Use to be the books are in red cover and hence redbooks. Will update latest redbooks on pSeries/AIX if my friend decided to do pass me the info.

p6-570 Technical Overview and Introduction.
http://www.redbooks.ibm.com/redpieces/abstracts/redp4405.html?Open

Intro: DS5000 Series. ISBN: 073843244X 666 pages
http://www.redbooks.ibm.com/abstracts/sg247676.html?Open

AIX Enterprise Edition Sys Admin Guide.ISBN: 0738432903 316 pages
http://www.redbooks.ibm.com/abstracts/sg247738.html?Open

p6-550 Technical Overview
http://www.redbooks.ibm.com/redpapers/abstracts/redp4404.html?Open

Utility Capacity on Demand: What Utility CoD Is and How to Use It

http://www.redbooks.ibm.com/redpapers/abstracts/redp4416.html?Open

PowerVM Virtualization Active Memory Sharing
http://www.redbooks.ibm.com/redpapers/abstracts/redp4470.html?Open

Understanding How AIX Manages Memory / Page Space

2009-06-16T06:31:00.000-07:00

Somebody ask me about paging space. So I went to google to find out more and found an article which i think is still relevant eventhough AIX is at 6.1. The article dated back in 2001.

Data is essentially held in pages of 4096b, and a page in RAM is accessible by the CPU, if the page is on disk the CPU can't access it directly. A page fault occurs when a wanted page address does not translate to a real memory address (i.e. the data you wanted is not there). At this point the Virtual Memory Manager (VMM)knows it needs to get data from disk and place it in RAM - it therefore checks to see that there is space in RAM in which to out this data.

If there's enough room, VMM checks to see if the wanted page has been used previously by this process:

- if not, an "initial page fault", VMM allocates _two_ pages for the data; one in RAM and the other on a backing page on disk where it can go if it has to be temporarily removed from RAM. This is known as "late page space allocation".

- if it has, a "repage fault" I/O is scheduled to bring the data back from disk and into RAM - the act of resolving this repage fault is called a "page-in" (the process that is waiting for this to happen is in a "page wait state").

So what happens if there's not enough room in RAM to put the page? Well the page stealer is there to ensure that there is a supply of free RAM pages available for an initial page fault. If the number of free RAM pages drops below a specified value then the page stealer will try and get some pages back. It keeps on stealing pages until it reaches an upper limit.

So how does it decide which pages to steal? The page stealer will select the least recently used, or LRU, pages. If the page has been modified in RAM it's classed as a dirty page and is put to a backing store (either page space or a filesystem); if it's clean (the copy in RAM matches the copy in page space) then the RAM page is purged.

Note that the page space is used for non-persistent or working pages, and the filesystem is used for persistent or file pages.

There is, of course, a basic assumption here that all stale pages are treated equally, i.e. whether it's a file- or nonfile- page makes no difference to the page stealer.

However this is not the case. Increased paging activity makes VMM act upon the different types of (stale) pages in a different manner. When the number of [stale] file pages exceed a number - set by the maxperm threshold - the page stealer will steal only file pages.

If the number of stale file pages is below maxperm (but above the set minperm threshold) then two other considerations come into play.

The VMM checks the repage rates of both file and nonfile pages, and will steal file pages if the file page repage rate is higher than the repage rate for nonfiles.

If this not the case then both types of pages are treated as equal victims.

PERFORMANCE HITS / ACTUAL DISK I/O...

To understand the performance hit of the paging figures that you come across, you need to realise that page faults do NOT (necessarily) result in disk activity. Remember from above that only the repage fault - the act of bringing back previously used data into memory - causes disk I/O to be scheduled.

Page out I/O only occurs when a page is stolen by the page stealer AND is marked as 'dirty'. This only happens when there is a shortage of free RAM pages. Hence the page-out figure can be an indicator of how memory constrained the system is. The vmstat command is only of limited use as it just reports activity concerned with page space (and not paging to/from filesystem space).

If the system consistently appears to hover around the minperm value (the "fre" column in vmstat) then it does not follow that the system is memory constrained - consider the scenario where an initial page fault is resolved by purging a clean, but stale, page. In this there is paging activity but no corresponding I/O.

System performance may be improved by reducing the amount of RAM that file pages occupy - this ensures that working pages are not continually being pushed out to make way for file pages.

This can be achieved through the use of the vmtune command (/usr/samples/kernel) and DECREASING values for minperm and maxperm.

PAGING SPACE

So how much page space do I need? For systems that have up to 256MB of real memory, use the well known formula...

page_space = 2 x real_memory

...for those systems with more than 256MB of real memory use...

page_space = 512MB + (real_memory - 256MB) * 1.25

The following should also be adhered to where possible:

1. configure just one paging space per disk
2. use between 2 and 6 paging spaces in a medium size system
3. configure the paging spaces on each disk to be the same size

That's about it really - all you never needed to know about paging space and VMM.

Dave V.

Thks dave for a good article in AIX paging. In my experience, which is not that much, for system that used Oracle, usually i will ensure that the paging space is 3 times of real memory. For Informix usually 3 times of real memory. As for DB2 just use default setting when you install AIX. For those who are really technical, try this for a change on Overview of AIX page replacement.
http://www.ibm.com/developerworks/aix/library/au-vmm/index.html

Where to find technical docs

2009-06-16T04:48:00.000-07:00

My first posting. Let see, when i ordered my pSeries machines, i cannot find those thick manuals that i used to get when i ordered pSeries machines (back then known as RISC6000). So i search the web and found this website.

http://publib16.boulder.ibm.com/pseries/en_US/infocenter/base/aix51.htm

Contains information on topics shown below and specifically on AIX 5.1
System Management Guides
Installation Guides
System User's Guide
Programming Guides
Product and Apps docs
Reference Doc
Technical References

If any of people out there wants to ask Qs pls post your comment. I will try to find out more. Good for you since somebody can answer your Questions and good for me cause i can brush up my skill in AIX.