a. db1 – concurrent users + processes = 410 b. db2 – concurrents users + processes = 50 c. db3 – concurrents users + processes = 50 The above three databases are going to be housed on one server. What is the best way to calculate the kernel parameters based on the above information ? Is there a formula for each of the kernel parameters? I see the below values in the preinstallation documentation but they do not specify the formula? Can you please help me with the formula? SHMMAX 4294967295 SHMMIN 1 SHMMNI 100 SHMSEG 10 SEMMNS 200 SEMMNI 70 SEMMSL Equal to the value of the PROCESSESinitialization parameter.
SHMMAX = The maximum size(in bytes) of a single shared memory
segment.
SHMMIN = The minimum size(in bytes) of a single shared memory segment. The above settings let the max be bigger then we wil ever use and the min much smaller. They are sufficient for pretty much all systems.
SHMMNI = The number of shared memory identifiers.
SHMSEG = The maximum number of shared memory segments that can be attached by a process. The above settings should also be sufficient.
SEMMNS = The number of semaphores in the system.
SEMMNI = The number of semaphore set identifiers in the system; determines the number of semaphore sets that can be created at any one time.
SEMMSL = The maximum number of sempahores that can be in one semaphore set. It should be same size as maximum number of Oracle processes (The PROCESSES parameter in the init.ora file).
SEMMSL Set to 10 plus the largest initsid.ora PROCESSES parameter of an Oracle database on the system. The PROCESSES parameter can be found in each initsid.ora file, loc ORACLE_HOME/dbs directory. The default value of PROCESSES for the 8.1.5 prebuilt database is 50. SEMMNS Set to the sum of the PROCESSES parameter for each Oracle database the largest one, plus 2 times the largest PROCESSES value, plus 10 number of Oracle databases. For example, consider a system that has three Oracle instances with the PROCESSES parameter in their initsid.ora files set to the following
values: ORACLE_SID=A, PROCESSES=100 ORACLE_SID=B, PROCESSES=100 ORACLE_SID=C, PROCESSES=200 The value of SEMMNS is calculated as follows: SEMMNS = ((A=100) + (B=100)) + ((C=200) * 2) + ((# of instances=3) * 10) = 630
SHMMIN = The minimum size(in bytes) of a single shared memory segment. The above settings let the max be bigger then we wil ever use and the min much smaller. They are sufficient for pretty much all systems.
SHMMNI = The number of shared memory identifiers.
SHMSEG = The maximum number of shared memory segments that can be attached by a process. The above settings should also be sufficient.
SEMMNS = The number of semaphores in the system.
SEMMNI = The number of semaphore set identifiers in the system; determines the number of semaphore sets that can be created at any one time.
SEMMSL = The maximum number of sempahores that can be in one semaphore set. It should be same size as maximum number of Oracle processes (The PROCESSES parameter in the init.ora file).
SEMMSL Set to 10 plus the largest initsid.ora PROCESSES parameter of an Oracle database on the system. The PROCESSES parameter can be found in each initsid.ora file, loc ORACLE_HOME/dbs directory. The default value of PROCESSES for the 8.1.5 prebuilt database is 50. SEMMNS Set to the sum of the PROCESSES parameter for each Oracle database the largest one, plus 2 times the largest PROCESSES value, plus 10 number of Oracle databases. For example, consider a system that has three Oracle instances with the PROCESSES parameter in their initsid.ora files set to the following
values: ORACLE_SID=A, PROCESSES=100 ORACLE_SID=B, PROCESSES=100 ORACLE_SID=C, PROCESSES=200 The value of SEMMNS is calculated as follows: SEMMNS = ((A=100) + (B=100)) + ((C=200) * 2) + ((# of instances=3) * 10) = 630
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