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Application buffer swaps and HP-UX swaps

Hello all,

I would like to consult with you regarding our production instance swaps on OS and on application level.

On application level, in transaction ST02:

1.GENERIC KEY BUFFER has around 300 swaps per week:

zcsa/table_buffer_area 60000000 Byte Size of generic key table buffer

zcsa/db_max_buftab 10000 Max. number of buffered objects

2.Program buffer has more than 15000 swaps perday: PXA

abap/buffersize 500000 kB Size of program buffer

abap/pxa shared Program buffer mode

3.Export/import (sometimes to 230000 swaps):

rsdb/obj/buffersize 20000 kB Size of export/import buffer

rsdb/obj/max_objects 20000 Max. number of objects in the buffer

rsdb/obj/large_object_size 16384 Byte Estimation for the size of the largest object

What is your opinion, should we increase the buffers sizes?

How much should be the abap/buffersize, regarding the fact that we have two production SAP instances on the same HP server?

Should we put for parameter ipc/shm_psize_06 = -10, segment 06 to be included in pool 10, currently ipc/shm_psize_10=24000000?

Should also the parameter ipc/shm_psize_02 = -10?

In note 37537:

“It is especially important that R/3 shared memories with numbers (keys) 02 and 06 are in the same shared memory pool.”

In note 103747:

“The enhancement of program buffers (abap/buffersize) can cause problems in the memory administration”

“With HP-UX you have to consider the following:

If the total out of program buffer and EM is higher than 1000 MB, the program buffer has to be in a pool:

if abap/buffersize + em/initial_size_MB > 1000 MB.

ipc/shm_psize_06 = -10 and

ipc/shm_psize_02 = -10

(This measure is necessary to avoid a Shared Memory fragmentation.)”

On HP-UX level:

hostname : sap_serv

model : 9000/800/N4000-55 (server)

CPU : (8) PA8600 550 MHz (PA-RISC 2.0)

RAM : 8 GB

OS : HP-UX B.11.00 (64-bit)

JVM : Java 1.3.1.12 (/opt/java1.3/bin/java)

The latest OS patches from March 2004 for HP-UX 11.00 are applied on the system.

sap_serv:/#swapinfo -tam

Mb Mb Mb PCT START/ Mb

TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME

dev 1536 0 1536 0% 0 - 1 /dev/vg00/lvol2

dev 20480 3563 16917 17% 0 - 0 /dev/vg00/lvswap2

reserve - 12455 -12455

memory 6217 668 5549 11%

total 28233 16686 11547 59% - 0 -

sap_serv:/#vmstat -S 5 5

procs memory page faults cpu

r b w avm free si so pi po fr de sr in sy cs us sy id

0 3 0 337169 7541 16728 16799 4 6 24 0 77 2917 4434 408 3 1 96

0 2 0 352031 7475 5 5 14 22 1 0 15 2675 4544 399 3 1 96

0 3 0 378783 7795 5 5 4 83 9 0 67 2662 7508 474 7 2 91

3 1 0 729871 8079 5 5 56 108 60 0 119 2733 15677 1002 9 3 88

2 2 0 719061 8007 5 5 36 34 28 0 38 2669 10557 741 9 2 90

sap_serv:/#

What do you think how to decrease swapping on our server?

Do you have some suggestions?

We have users complains regarding the SAP application performance. We need to determine the reason if it is connected with the swapping problems.

Thank You in advance.

Best Regards,

Ruzica Kalkasliev

Former Member

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