AIX

As shockneck said and I also stated in my 1st post - it is very important (lru_file_repage=0).

Also it doesn't do any harm to set

Code:

chdev -l aio0 -a maxreqs=32768 -P

so you run against limits if you get high AIO-traffic on this box.
If not tuned already, it doesn't harm either to have some more AIO-servers available, just in case. Maybe start with:

Code:

chdev -l aio0 -a maxservers=30 -P
chdev -l aio0 -a minservers=3 -P

Also this is not optimal - if it is a noticable impact I can't tell but it can be fixed:

Code:

14856 pending disk I/Os blocked with no pbuf
57593 paging space I/Os blocked with no psbuf
2228 filesystem I/Os blocked with no fsbuf
33150 client filesystem I/Os blocked with no fsbuf
9204 external pager filesystem I/Os blocked with no fsbuf

Depending on if you use JFS or JFS2 there are those parameters to increase the buffer size so you less or preferably no of these blocked buffers like up there. Again, check out Jaqui Lynchs initial tuning guide I already posted.

I think alot of VMTUNES vmo ioo information has been gathered in this thread.

1) Does anyone know of any good document or redbook on this subject ?

2) Does Oracle have any document specific for this ?

Thanks

there are a lot of good whitepapers and how-to's on the IBM pages - maybe have a look here : http://www-03.ibm.com/servers/enable.../9a46/9a46.pdf or http://www-03.ibm.com/support/techdo...Index/WP100883 - but all this can be only a guide since system tuning happens on the system, not on some whitepapers ... and it depends widely as well on what exact AIX TL/SP you are running - since a lot changed with TL2 and TL5 for AIX - so tunables for earlier versions might not be that optimal any more - and it depends as well on your hardware / infrastructure and the kind of workload and the oracle settings themselves in the system. You might want to have a look here Jaqui's AIX Performance and Security Blog - Jaquie might be THE IBM goddess of system tuning - we're running most of these values with a bit finetuning on our 160 oracle lpars - only a few servers have very particular requirements where we had to amend widely.
I would go as well with all recommendations made previously (though I would indeed set the min/max values to 1-3 and 90 if its an oracle-only system). Have a look on your buffer sizes, make sure that oracle is set to use asynch IO since this is reducing the waits immensely, you might want to set oracle to manage if its using cio or not instead of AIX, make sure that your redo-logs (and controlfiles) are in a filesystem with smallest possible blocksize and that you use different filesystems for archivelogs, redologs, datafiles and dumps each, put as much load as you can onto your system and start tuning.
That means - monitor - amend - monitor - amend further or revert - have users testing and sharing their feelings using the database ... until your system fulfills your and your user's expectations. Make sure your SGA sizes are not too small but also not too big as this is contraproductive as well - make sure your AVM remains around 70% - yes oracle needs filecaching even when you're running cio on filesystem base ...
Kind regards
zxmaus

Check the Redbook pages of IBM and enter "AIX Performance" as search string. For database, especially Oracle tuning just add database or oracle to it when searching the Redbooks.
Also again: Check Jaqui's guide to initial tuning as said by the former poster and me now the 3rd time

Also there those on scribd.com:

Moderator's Comments:

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Oracle/AIX Performance and Tuning

Applied what zaxxon and shockneck suggested and saw the difference in performance.

--
One another system, i have DISK utilization 100%

How can i reduce this ?

DISK______________BUSY
HDISK0____________100%

Thanks

Hi,

is this rootvg and do you possibly have not enough memory and are paging to disk? Than add memory and your disk usage will go down.
If you have enough memory and the system is not paging and this is internal diskspace and rootvg - than add another disk to rootvg to split the workload.
Additionally put here the last 8 lines from output from vmstat -v - you might only need to add some more buffers.

Rgds
Nicki

As zxmaus says. Your pgspout is very high so it draws down your rootvg overall. Your 6GB has 90% computational pages and is using paging space as stated.

I guess there is not that much of tuning possible, but getting more RAM into the box.
Nevertheless you might post following output:

Code:

vmstat -vs
vmo -x| grep -iE "minperm|maxperm|lru_file|poll"

and tell us what kind of application runs there.