Hi to all ;
Kernal values formula for oracle 10g database on OEL4
I asked many DBAs regarding this question. Few persons saying right,
MAny peoples saying it's wrong. Given formula is right or not
There are two main components
Shared memory : SHMMAX , this should be more than the size of your memory structures.
Semaphores : As a DBA we don't know how many users will be accessing one database concurrently.
g. SHMMAX = (SGA+PGA)Instance size of all the database + 30% of the instance size.
eg. If i have 3 databases and sizes are
For DB1 SGA=3G , PGA=2G
For DB2 SGA=1G , PGA=3G
For DB3 SGA=1G , PGA=1G
So , SHMMAX will be (3+2+1+3+1+1)= 11G + 30%(11G)=round(11G+3.3)= 15G.
we need to get the approximate value from client. This can be calculated using
Semaphores = (processes of all DB ie.processes parameter from DB)*2 +10*no.of databases
eg. If i have 3 databases with processes parameter
For DB1 = 800 , DB2=1200,DB3=500
(800+1200+500)*2+10*3 = 2500+30=2530