Complete Checklist for Manual Upgrades to 11gR2 (Doc ID 837570.1)

https://support.oracle.com/epmos/faces/DocumentDisplay?_afrLoop=550009615142183&id=837570.1&_afrWindowMode=0&_adf.ctrl-state=igytrxho8_97


Determine PFILE or SPFILE is used to start up database.

SQL> show parameter spfile;
SQL> SELECT DECODE(value, NULL, 'PFILE', 'SPFILE') "Init File Type"
FROM sys.v_$parameter WHERE name = 'spfile';