Upgrading RAM from 2 to 4GB and 2 more CPUs advice sort 1

[jpor]

Hello Gurus.

I currently administer a RS6K H70 Machine running AIX 4.3.3 on ML 9, which currently has 2 x 340Mhz POWER RISC 64 II chips and one card with 2GB RAM.

Am I right in saying that when the RAM is upgraded to 4GB I will need to up the Swap File ? And if so is it vmtune I use ?

Also Will I need to configure anything else so that the O/S will see the other 2 CPUs ?

Thanks in advance.






( "To become Wise, first you must ask Questions&quot

 

[haexpert]

You should increase paging space as the good book states it should be 2 x physical RAM.

The additional CPU's will be detected and configured automatically.

I would also review the size of the dump area as this usually needs increasing when RAM and/or CPUs are added.
use sysdumpdev -l to list current dump devices and
sysdumpdev -e to give the new dump size (I usually double the estimated dump size).

 

[jpor]

Thanks haexpert.

But what is the command syntax for the upping of paging space ?


( "To become Wise, first you must ask Questions&quot

 

[dlpar]

If you are not familiar with AIX, use smit:
smitty pgsp

But if you really use the paging space you have to place hd6 on the middle of your disk (lspv -p) to improve the performances.

 

[jpor]

Thanks dmarais.

I'm getting there. New to setting up paging space.


( "To become Wise, first you must ask Questions&quot

 

[jpor]

Okay I have had a look at the smit option Change / Show Characteristics of a Paging Space
One question:

I currently gone onto hd6. And have the following:

Paging space name hd6
Volume group name rootvg
Physical volume name hdisk1
NUMBER of additional logical partitions [] #
Use this paging space each time the system is yes +
RESTARTED?

When it asks for Additional logical partitions, I take it this is worked out from the free PP list ?

Or am I in the wrong option ?

Any help on this would be most appreciated.


( "To become Wise, first you must ask Questions&quot

 

[alexhu]

Before you add more - how much are you using ?

Use lsps -a to find out

Page Space Physical Volume Volume Group Size %Used Active Auto Type
paging01 hdisk16 datavg7 800MB 81 yes yes lv
paging00 hdisk5 datavg6 800MB 81 yes yes lv
hd6 hdisk0 rootvg 1024MB 63 yes yes lv

If the system is busy and the %'s are not too high - then why add more ?

Alex

 

[alexhu]

Yes - I am going to add a bit more to this system

Alex

 

[jpor]

Thanks alexhu.

Currently get the following:

Page Space Physical Volume Volume Group Size %Used Active Auto Type
hd6 hdisk1 rootvg 2048MB 15 yes yes lv

Although I have read that you are supposed to have x2 the space compared to RAM on the system. I.e I should really be using 4096 page space.


( "To become Wise, first you must ask Questions&quot

 

[alexhu]

The x2 swap space compared to RAM is a 'rule of thumb' and so its not hard and fast. If your machine doesn't need it, why configure it.

However, in the event of a system crash, swap space is used to dump the memory to before copying it out to /usr/dump

So, how often does your system crash ? and how much memory is used anyway ? AIX uses a lot of memory for filesystem caching, so I would think that that part is not written to a system dump.

By all means make your swap the same size as your memory, certainly no bigger, unless you have lots of disk to waste

By the way you were using the correct option to increase the size, but another 'rule of thumb' says don't use more than 20% of a disk for paging - how big is that disk ?

Alex