Hi..

After creating the new instance, when i try to initilised the shared memory i got the below message

For disk space initialization, the value specified in the ONCONFIG file for
PHYSDBS (physlog) should be equal to that of ROOTDBS (rootdbs).
oninit: Fatal error in shared memory initialization



do we need to keep always both the values are of equal size.

ChanduP

Absolutely not!

The physical log is at initialization time a part of the rootdbs.
So the size should be at least smaller than the rootdbs. After initialization, you should change the location of your physical log from the rootdbs to another dbspace, like the physdbs.
Set the correct parameters in the onconfig too.

The ROOTDBS should greater than the physical log by atleast 30MB (to be safe) if your physical log is to be placed in the ROOTDBS. If you try to place the physical log to a separate space such as PHYSICALDBS, the total physical log size should be the size of your PHYSICALDBS. For best practices it should be separated, separted by disk is much better.

I hope I have answered your question well.