Shared memory configuration for Tru64 and Oracle 8i

From: Schwarzkugler, Bernd <Bernd_Schwarzkugler_at_ibex-ag.de>
Date: Tue, 03 Apr 2001 14:57:42 +0200

Hi,

i've writen a Howto for configuring shared memory on a Tru64 5.x system.

Would you like to say some additional words about this text?

Oracle 8i Performance Tuning under Tru64 UNIX Version 5.x
=========================================================

I. Requirements for the Oracle 8i database:

Taken from the Oracle8i Administrator's Reference Guide:

The maximum size of a single shared memory segment is specified by the
parameter SHMMAX.
Oracle Corporation recommends a value of 2139095040 for SHMMAX regardless of
the amount of
memory on the system.

SHMMAX 2139095040 The maximum size (in bytes) of a single shared memory
segment.
SHMMIN 1 The minimum size (in bytes) of a single shared memory segment.
SHMMNI 100 The number of shared memory identifiers.
SHMSEG 32 The maximum number of shared memory segments that can be attached
by a process.


II. How to the IPC parameters at kernel runtime.

>From the command line:
The command 'sysconfig -q ipc' gives information about the IPC settings.

# sysconfig -q ipc
ipc:
msg_max = 8192
msg_mnb = 16384
msg_mni = 64
msg_tql = 40
shm_max = 4194304
shm_min = 1
shm_mni = 128
shm_seg = 32
sem_mni = 16
sem_msl = 25
sem_opm = 10
sem_ume = 10
sem_vmx = 32767
sem_aem = 16384
max_kernel_ports = 38432
ssm_threshold = 8388608
ssm_enable_core_dump = 1
shm_allocate_striped = 1
shm_enable_core_dump = 1

>From dxkerneltuner (a X11 program):

double click on the ipc line, it will popup a window with the current
settings and
boot time values and min and max value.


III. How to set the required parameters:

>From the command line:

Edit /etc/sysconfigtab and add the following lines:

ipc:
        shm_max=2139095040
        shm_mni=100
        shm_seg=32
        shm_min=1


>From dxkerneltuner:

Just correct the values, click apply.

IV. (Recompile the kernel and) reboot the system

The recompilation of the kernel is advised in the Oracle 8i System
Administrator Guide.
In my opinion the recompilation of the kernel is not necessary.

Review the settings you made with 'sysconfig -q ipc'


Greetings

Bernd Schwarzkugler
UNIX Spezialist
IBEX AG
Tel: 08207/9611-418
Received on Tue Apr 03 2001 - 12:58:58 NZST

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