Tom,

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.  

Thanks,
Sing


and we said...


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

别怪俺翻贴。
想知道细致一些，这些参数的设置不当会有什么后果，这些参数在oracle的官方文档里面有没有详细的解释。可否告知文档号。