Data Protection: A Plethora of Alternatives, but Which Ones are Right for You?
by Claus Mikkelsen on Mar 14, 2013
Ros Schulman, Data Protection product line manager at HDS, and I, in conjunction with David Merrill, are exploring the economics of data protection in a series of blogs. David will focus on economics while we focus on the technology and practices.
“It depends”–an age old answer, and there are no black and white rules, but data protection is like short-term insurance – the more precious the data asset and the higher the risk, the higher the premium paid to ensure uninterrupted access to that data.
Let’s begin by looking at some of the many options out there and try and to break it down. Why do we protect data? Well that’s simple. In case something happens, we need to recover that data. Wouldn’t you be upset if you lost your phone and didn’t have a backup of your contacts? We also need to keep data for regulatory reasons, but either way it’s the recovery process and how long it takes that counts.
So what are our choices? We have traditional backups, remote copies, backups on disk, snapshots, VTLs, copies here, copies there, copies everywhere, but sometimes not when you need them or not in a form from which you can recover quickly. One of the things to consider is the difference between a backup copy and something that is actively being copied to. A backup copy is typically made at a specific point in time, traditionally to tape, nowadays often to disk. The benefit of these backups is if the original data gets corrupted or deleted, you can restore it from the copy. In an active copy scenario, often used for disaster recovery, the copy is also subject to the same issues as the original. So do you need both? Well here it comes again. It depends on your requirements for recovery. If you have plenty of time to recover and don’t require data to be current after recovery, then using more traditional backup methods for both local backup and disaster recovery may be an option. If you need your systems to be up in a very short period of time, and the data to be current, then you will need active copies for disaster recovery and something like snapshots versus traditional backup for local recovery.
One thing to remember with an active copy is that if the primary data gets corrupted, the second copy will also be corrupted immediately afterwards. That’s why active copy for disaster recover should never preclude traditional backups. A few years ago, a team of us visited a large bank (at the time they were not an HDS customer; they are now). Their problem was that they were mandated (by senior management) to suspend nightly backup activity as a cost savings measure since they were already doing remote replication. And as you would expect, their primary database got corrupted, as did the second copy. Immediately!
So just like insurance it comes down to cost versus risk. To help determine the right mix of data protection solutions, the business needs to ask:
- How critical are those systems?
- What is the cost of recovering them in an hour versus the cost of recovery in 24 hours?
- Is the cost of recovery more than the cost of the system going down?
Next in the series, we will further discuss some of the different technologies. And we’re sure “prolific blogger-Merrill” will be chiming in as well.
Ros Schulman has over 33 years experience in the IT business both on the vendor and customer side. This has included systems programming, operations, technical support and sales support. Schulman has worked at Hitachi Data Systems for almost 21 years. She currently works in the Global Solutions Strategy and Development organization with responsibility for Data Protection Software including Disaster recovery and backup software. She spends much of her time with customers, discussing their unique Data Protection challenges. She has also co-authored many white papers in the area of Business Continuity. Schulman is also a Certified Business Continuity professional and has met all the requirements as designated by the Disaster Recovery Institute.