hello all,

We are increasing the RAM from 8Gb to 32Gb on the HP-UX 11.11
server.Just a quick question...should we be tuning informix to reflect
the increase in memory?
current settings are....

SHMVIRTSIZE 2784000
#SHMADD 128000
SHMADD 256000
EXTSHMADD 8192
SHMTOTAL 10000000

Thanks in advance.

Hello, you should check how is your engine running with 8Gb, first.
Eg: 1) check how many memory segments are you normally using?
That should give you a great tip on how you could resize your SHM
parameters (as least shm segments, better for you).
2) are you bufferpool enough for your concurrent sessions? check it
out... then increase it, according to your new memory limits.
3) your SHMTOTAL parameter should be changed, of course....

Hope it helps.
Best regards.

Em 27/07/2011 11:43, howie.lfc (AT) googlemail (DOT) com escreveu:

--

Alexandre Marini

Tecnologia da Informação - DBA

msn: alexandre_marini (AT) hotmail (DOT) com

SEFAZ-MS / SGI-UGSR / Sistemas IBM-Informix

<Cert-Info-Mgmt_color.jpg>

IBM Certified System Administrator - Informix Dynamic Server V10 / V11 /
V11.70

IBM Information Management Informix Technical Professional v3

I would only adjust SHMVIRTSIZE and SHMADD if a) your server tends to add
virtual shared memory segments over time or during busy periods or b) you
want to increase the amount of memory available for non-pdq sorting
(DS_NONPDQ_QUERY_MEM) or for PDQ query processing (DS_TOTAL_MEMORY)

Increasing buffers to take advantage of more memory to keep more of your
working set of data in memory will improve performance IFF the entire
working set of data is not already kept in memory with the current buffer
pool. Looking at your BTR metric values and the output of onstat -P over
time can help you determine this.

Art

Art S. Kagel
Advanced DataTools (www.advancedatatools.com)
Blog: http://informix-myview.blogspot.com/

Disclaimer: Please keep in mind that my own opinions are my own opinions and
do not reflect on my employer, Advanced DataTools, the IIUG, nor any other
organization with which I am associated either explicitly, implicitly, or by
inference. Neither do those opinions reflect those of other individuals
affiliated with any entity with which I am affiliated nor those of the
entities themselves.



On Wed, Jul 27, 2011 at 11:59 AM, Alexandre Marini <
amarini (AT) fazenda (DOT) ms.gov.br> wrote:

"howie.lfc (AT) googlemail (DOT) com" <howie.lfc (AT) gmail (DOT) com> wrote

Generally you wouldn't change any of these unless you're changing the
application and/or onstat -g seg shows that you already need multiple
segments. I'm guessing you don't have issues here since you already have
SHMTOTAL set to more memory than you have in the box.

The most likely things you would change to exploit extra memory, all else
being equal, would be BUFFERS.

If you are on Workgroup/Growth edition you cannot allocate more than a total
of 16g to any one instance anyway, and to stay within the Informix rules you
should limit the allocation across ALL instances on the server to 16g.