In the last week, I had couple of my customer ask me the same question: how can we move our data files between disks with minimum downtime?
This is actually a really good question. When we want to move a database around (let’s say to a new storage or a new disk device) we will need to do it when the files are closed (offline or database down) in order to keep them consistent. We can do it tablespace by tablespace or the entire database but at the end, it all depends on the size of the files that needs to be transferred. By the way, in Oracle 12c this problem is obsolete since there is an online move command
In the example I’m giving here, the customer had a 3 TB database with most of it in the same tablespace. The downtime allowed by the customer SLA to his customers was around 5-7 minutes so we obviously couldn’t take the database down or take the tablespaces offline. We needed another solution.