Oracle parameters in pfile and sfile

Oracle spfile and pfile concepts:

Oracle instance starts with initSID.ora file. But,Oracle will start with spfile, If spfileSID.ora exists in <home folder>/dbs

How to create spfile?
How to do changes in pfile?
How to create pfile?


Answer:
sqlplus "/ as sysdba"
sqlplus>shutdown immediate;
sqlplus>create pfile from spfile;
sqlplus>exit;

<home folder>/dbs#vi initSID.ora

sqlplus "/ as sysdba"
sqlplus>create spfile from pfile;
sqlplus>exit;

Start Oracle Instance Now.

Now, Oracle will always start using spfileSID.ora file.

What is the sequence to start oracle?

Answer:
Sequence to search a file in oracle home filder is

spfileSID.ora
spfile.ora
initSID.ora
init.ora

If none of them found, oracle will fail to start.

Dharmendra Kumar