Re: Slightly OT: Multiple database on one UNIX system

From: Suzy Vordos <lvordos_at_qwest.com>
Date: Tue, 04 Feb 2003 08:44:07 -0800
Message-ID: <F001.0054349F.20030204084407@fatcity.com>

If it helps, here is how to calculate semaphore & shared memory parameters. This is based on white papers written by Adrian Cockcroft and also his book Sun Performance and Tuning.

These settings allow up to 4000 oracle processes (background, dedicated connections, etc.).

• ----------------------------------
• Semaphores/Shared Memory for ORACLE
• ----------------------------------
• shmmax = max size per shared memory segment
• shmmin = min size per shared memory segment
• shmmni = max num shared memory identifiers
• shmseg = max num shared memory segments per process
• semmns = max num semaphores system wide (=semmni*semmsl)
• semmni = max num semaphore sets system wide (=semmnu)
• semmsl = max num semaphores per semaphore set (=semopm)
• semmnu = max num sempahore undo structures (=semmni)
• semmap = max entries per semaphore map (=semmni*semmsl)
• semopm = max operations per semop call (=semmsl)
• semume = max undo entries per process (=semopm)
• semvmx = max value of a semaphore (cannot be > 32767)

forceload: sys/shmsys
forceload: sys/semsys

set shmsys:shminfo_shmmax=4294967295
set shmsys:shminfo_shmmin=1
set shmsys:shminfo_shmmni=100
set shmsys:shminfo_shmseg=10

set semsys:seminfo_semmns=4000
set semsys:seminfo_semmni=40
set semsys:seminfo_semmsl=100
set semsys:seminfo_semmnu=40
set semsys:seminfo_semmap=4000
set semsys:seminfo_semopm=100

set semsys:seminfo_semume=100
set semsys:seminfo_semvmx=32767

> "Godlewski, Melissa" wrote:
>
> Sun Solaris 8
> Oracle 9i
>
> Where can I find information about, a SUN Solaris 8 UNIX on how much
> memory can the kernel address? I'm wondering what the semaphore and
> shared memory settings for the SUN OS config file need to be when
> running multiple (20-30)databases on one physical machine. My current
> settings are from the Oracle install guide for 1 database only. Any
> help appreciated.
>
>
> * Oracle
> set shmsys:shminfo_shmmax=4294967295
> set shmsys:shminfo_shmmin=1
> set shmsys:shminfo_shmmni=256
> set shmsys:shminfo_shmseg=10
> set semsys:seminfo_semmns=1024
> set semsys:seminfo_semmni=512
> set semsys:seminfo_semmsl=512
> set semsys:seminfo_semvmx=32767
> * Oracle End
>
> /etc 330$ipcs
> IPC status from <running system> as of Fri Jan 31 11:14:35 EST 2003
> T ID KEY MODE OWNER GROUP
> Message Queues:
> Shared Memory:
> m 23808 0x5ec12124 --rw-r----- ora oraclei
> Semaphores:
> s 24576000 0x4c12445c --ra-r----- ora oraclei
> s 6094849 0x4c12445d --ra-r----- ora oraclei
> s 6094850 0x4c12445e --ra-r----- ora oraclei
>
> Memory: 16G real, 12G free, 2576M swap in use, 12G swap free

-- 
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-- 
Author: Suzy Vordos
  INET: lvordos_at_qwest.com

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Received on Tue Feb 04 2003 - 10:44:07 CST