Oracle database administrators face a number of challenges, but for Mel Shum, their biggest challenge is clear.

“The big pain point is availability,” said Shum, a Backup and Recovery Technical Consultant at EMC “Applications write to the database, the database gets bigger and bigger, yet the backup window at best stays static or at worst gets smaller because more and more people are using that database application.”

Shum, speaking live inside theCUBE from the floor of Oracle OpenWorld 2011 in San Francisco, helps Oracle DBA’s manage challenges of availability, backup and recovery. “DBAs are faced with bigger and bigger databases with shrinking backup windows and shrinking recovery windows and they have a conundrum as of what to do,” Shum told Wikibon’s Dave Vellante.

The result is that most DBA’s are control freaks. “They’re control freaks and they’re paranoid that they’re trusting a backup administrator with their data and essentially trusting them with their jobs,” Shum said. “They secretly stash away their own little copy just in case.”

But databases are getting too large for secret stashes. One tool to help is RMAN, which debuted with Oracle 11g. Shum explained:

Essentially what that is is they take an image-level backup of the database. So they take the hit initially. So subsequent to that, once that’s done they only do incremental changes to the disk backup device and actually apply those disc changes to the image to update to a more recent copy. So if I have a Sunday copy of my database and I did a Monday incremental, then what I do is I apply the Monday incremental to my Sunday image copy and have it update it and advance it to a Monday image copy. That works really well because if I have a 100 TB database but only one TB has changed, I’m only sending over one terabyte … but I get a yield of full backup.

Shum also expounded on some basic backup best practices that sometimes get overlooked. Namely, “You don’t have real backup unless it’s on separate media,” Shum said.

Check out the entire interview below:

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