we are running our database on 10.2.0.2.0 now we want to upgrade to 22.214.171.124. the server is having 4 instances with 500mb instance size and 4gb of ram. i checked hardware prerequisites, they given like minimum 1gb ram and 5.1gb disk space for db. of-course i have enough space for my databases. now do we need to increase the ram size and instance sizes also 11g.
You should upgrade to V12.1 instead.
Do you really want to upgrade to 126.96.36.199? And not 188.8.131.52?
There is a bug for AIX that processes consume more memory (related with online patching), fixed in later releases.
Also its suggested to increase ASM memory target to 1GB (default for 184.108.40.206.6)
I would not suggest to upgrade any production env to 12c. (unless you want to be a hero) Wait for 12.2