We are going from 188.8.131.52.1 to 8.1.6 on the same server.Does upgrade work fine or do I need to Knock down everything(which I can do as production is already shifted to different server(s)) and start from bottom up?
I prefer an Export, clean de-install, clean install, import - if it's a feasible way of doing things in your situation. This method gives you the chance to re-organise a little if you need to, defrag tablespaces etc...
When our instances are upgraded here, then Migration utility is used, but only because it's quicker than the above method.
I just did an 8.0.5 -> 8.1.6 upgrade with export/import. It takes a while as TerryD mentioned, but you can at least accomplish the bulk of it while the other database is running if you can't afford the downtime. Of course doing it that way requires more work/understanding than just taking the database down to others, exporting a full consistent database, and importing into a new one.
I didn't use the migration utility because of sysadmin issues but I've heard it's also very nice to use.
It depends on the situation. By far, the migration utility is much faster. However, it migrates your existing database warts and all.
The imp/exp method allows you to fix wrongs created by others. You may need to change the db_block_size or you may need to resize objects. However, depending on the size of your db, you might be waiting a long time.
I have used both extensively. Both methods work well for what they are intended.
thanks for your replies folks.that was helpful.
I think I missed the obvious and u just helped me to bring it to the fore .
I will not be able to change the db_block_size if I just migrate--- right?