So you keep the backup files in place on another NAS, just in case. But unless you revisit that backup weeks later, there's a good chance it will be forgotten, lost under a pile of new work and new problems, and this massive backup won't be rediscovered until someone needs more space on the other NAS. When someone goes picking through the files to see what it is, they'll rightfully be concerned about deleting that data, since it looks important. Unless everyone knows what went on and why that data is there, it will likely be left alone, taking up space and potentially even becoming a security risk, because it may contain sensitive data.
This situation is all too common. It happens in large infrastructures and small. With the prevalence of huge disk and cheap NAS devices that are essentially used as enormous USB drives when performing certain tasks, it's not unlikely you'll find copies of data in places you weren't even sure you had places. Heck, I recently discovered a few terabytes of data that had wound up on a 24TB NAS, on an NFS export below the main export path, essentially invisible unless you knew where to look. I'm still not sure how it wound up there, but looking at the dates, I figure it's been hanging around for two years.
The bright side to having multiple backups of certain file stores: They can save your bacon if something goes wrong. The downside is the accumulation of wayward piles of data, needlessly consuming resources and presenting a potential source of confusion or even a security risk -- all because of the general feeling that you don't quite want to delete that backup just yet, because you might need it, particularly in a hurry.
All it takes is a little organization and perhaps some scheduled reminders -- when it comes down to it, all we're talking about is doing a little cleanup from time to time. But when you're in the thick of it and moving a mile a minute to rectify a blocking problem, it's very easy to forget to stop and take care of the little things.
Face it: Many IT pros are packrats when it comes to data. We'd rather add disk and save our backups than delete them to save space. We've all been burned by data loss at least once before, and it's a painful memory. Maybe that's why I have my laptops, desktops, and servers backed up to multiple destinations on a recurring basis. It's a good idea, but I guarantee that I have file stores squirreled away in places that even I'd be shocked to find. Once bitten, twice shy.
This story, "Beware of backups that come back to bite you," was originally published at InfoWorld.com. Read more of Paul Venezia's The Deep End blog at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.