how to caculate resident shared memory size?

how to caculate resident shared memory size?

Post by sqs » Sun, 31 Dec 1899 09:00:00



hi,all
could you tell me how to caculate resident shared memory size?

thank you.

 
 
 

how to caculate resident shared memory size?

Post by Mark D. Stoc » Sun, 31 Dec 1899 09:00:00



> hi,all
> could you tell me how to caculate resident shared memory size?

If you are running on UNIX, then onmonitor will tell you:

        Parameters->Shared Memory

The total is at the bottom left.

Cheers,
--
Mark.

+----------------------------------------------------------+-----------+
|Mark D. Stock - Informix SA       http://www.informix.com |////////  /|

|http://www.iiug.org   +-----------------------------------+////  / ///|
| Tel: +27 11 807 0313 |What year 2000 bug? year 2000 bug? |///  / ////|
| Fax: +27 838250 2325 |year 2000 bug? year 2000 bug? year |//  / /////|
|Cell: +27 83 250 2325 |2000 bug? year 2000 bug? year 1900 |/  ////////|
+----------------------+-----------------------------------+-----------+

 
 
 

how to caculate resident shared memory size?

Post by Art S. Kage » Sun, 31 Dec 1899 09:00:00



> hi,all
> could you tell me how to caculate resident shared memory size?

Mark Stock is correct about onmonitor if the engine is online.  You can
also use onstat -g seg and check the size of the class 'R' segment
which is the resident segment.  In addition the UNIX command ipcs will
report the various segment sizes (SEGSZ column) the engine is using:

ipcs -ma | head -3; ipcs -ma | fgrep informix

The resident segment is the first segment defined for the server in
question, the one whose key ends in 4801.  If you have multiple servers
the first four digits of the key indicate the SERVERNUM of the server
to which the segments belong (0x5256 + hex(SERVERNUM)).  Also note that
a few versions of some UNIX systems will not report all segments owned
by group informix but user root if you run ipcs as informix.  So if you
start your engine as root you may have to run ipcs as root.

If you are trying to determine the resulting resident size of various
ONCONFIG parameter settings before bringing an engine online there is
a calculation in the Informix Administrator's Guide you can use.  The
manual section also explains which ONCONFIG parameters affect the size
of the resident segment.

Art S. Kagel

 
 
 

1. Shared Memory Size vs Physical Memory Size

Can somebody please explain the pros and cons of increasing either the
initial virtual memory segment or adding a further segment via "onmode -
a" on a machine that is Informix Dynamic Server dedicated. Our
calculated shared memory size, as can be seen below, is only some 50%
of our actual physical memory. Any pointers/hints would, as ever, be
much appreciated. We have two instances running (LIVE and TEST) - see
outout from onstat below. Our Informix application connects via shared
memory.

ICL Teamserver M754i
SCO Openserver 5.0.4 (finally Y2K compliant ! as at yesterday !!)
Informix Dynamic Server 7.30.UC2
640Mb RAM

LIVE
onstat yields 258048 Kbytes

TEST
onstat yields 90112 Kbytes

As can be seen, the sum of the above is somewhat less than 640Mb.

Regards
Glyn Balmer

--
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pull the emergency 'chute first?

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