Oracle Database Upgrade Interview Questions?

1)For database projects, what are the biggest challenge?

Downtime for upgrade is a biggest challenge.

2)What kind of upgrade project you have done so far? 

I have work for almost all type of upgrade: RAC and non-RAC . OLTP and DW .Small database and large database.

3)What were the size of database?

 From 1 TB -15 TB

4)How long it will take to upgrade 2 nodes RAC database of 10 TB size?

Basic upgrade is independent of volume of database but depend mostly on number of components.

5)Can you please explain some of the issue you faced for DB upgrade?

Performance issue after upgrade is a major concern.

Error related to timezone

6)What are the different method for upgrading DB?

Manually or using DBUA.

7)Which one you prefer and why? 

I generally prefer manual .Reason: to have more control over the steps of upgrade.

8)One major difference between upgrading DB manual vs DBUA?

Manual process : we need to set cluster_database=FALSE but when upgrading via DBUA cluster_database=TRUE

9)One parameter which once set, cant be revert back but need to recover database from last backup.

COMPATIBLE

10)In which months oracle release CPU patches?
 JAN, APR, JUL, OCT

11) In which mode you  will start your database for upgrading from  10x to 11x?

Startup upgrade

12)Why not in startup migrate?

startup migrate was used to upgrade a database till 9i.But from 10G  we are using startup upgrade to upgrade database.

13)Can we apply PSU on database without applying PSU on grid  in 11.2.0.4?

No, unfortunately, you need to apply the PSU patches to both the grid-home and the rdbms-home as sometimes these patches contain fixes for a bug in both homes.