RE: Multiple instances - Sun Solaris: shmsys and semsys settings

From: Troiano, Paul (CAP, GEFA) <Paul.Troiano_at_gecapital.com>
Date: Thu, 29 Nov 2001 09:04:08 -0800
Message-ID: <F001.003D0A88.20011129083524@fatcity.com>

here is the excerpt from my /etc/system file, we currently have 12 instances on it. Be sure to apply the logic in the comments and not the actual values that I used. The settings will make sense to your SA. The logic comes from reading many papers on the subject (I have them around here somewhere).

This is a Sun E5k with 2.5 GB memory, 10 processors running Solaris 2.6 with both 8.0.5.2.1 and 8.1.7.1.0 Oracle databases. I use the same logic on all our systems.

HTH
- Paul

• Revised Shared Memory parameters *--------------------------------------------------------------------
• Maximum shared memory size. Set to maximum allowable on
• a 32-bit system. Its easier to remember the value in Hex. set shmsys:shminfo_shmmax=0xffffffff
• Minimum shared memory size. Always set to 1 byte. set shmsys:shminfo_shmmin=1
• Number of shared memory identifiers to pre-allocate. Set to handle
• 200 users for 6 instances or 100 users for 12 instances (1200) +
• 10 background processes each (60) + 20 for Sybase + 10% (130)
• = 1410 -> 1500. set shmsys:shminfo_shmmni=1500
• Maximum number of shared segments per process. Set to Oracle
• recommendation. However, I recall reading that only a maximum
• of 10 is allowed in Oracle. ?? set shmsys:shminfo_shmseg=20
• Revised Semaphore parameters *--------------------------------------------------------------------
• Number of semaphores in the system. Set to the shmmni setting x 2.
• Oracle needs this extra in order to start up. set semsys:seminfo_semmns=3000
• Maximum number of semaphores per semaphore group. Set to the
• maximum number of process per instance. set semsys:seminfo_semmsl=200
• Maximum number of semaphore identifiers. Must be at least semmns/semmsl
• (=15) but want to allow for many semaphore groups with less
• than the maximum number of semmsl. set semsys:seminfo_semmni=100
• Number of entries in the semaphore map. Pre-allocate the semaphores.
• Set to semmns. set semsys:seminfo_semmap=3000

-----Original Message-----
Sent: Wednesday, November 28, 2001 9:05 AM To: Multiple recipients of list ORACLE-L

Hi -

We are running a solaris server (2.6) for our develoment environment. We currently have 5 instances on the server. When we create another instance and try to start it, we get a ORA-27101: shared memory realm does not exist. The text reads 'Unable to locate shared meory realm'.

We have set the following kernal parameters to what we believe to be appropriate.

SHMMAX=1207959552
SHMMIN=1
SHMSEG=10
SEMMNI=100
SEMMSL=350

SEMMNS =1000
SEMOPM =100
SEMVMX=32767 Does anyone know of any other kernal parameter settings that may be causing this error?

THanks -
Lisa

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Received on Thu Nov 29 2001 - 11:04:08 CST