I've heard about the problem RAID has with ever increasing storage sizes on a few podcasts, and now I've run across Henry Newman's piece on the matter:

The bottom line is this: Disk density has increased far more than performance and hard error rates haven't changed much, creating much greater RAID rebuild times and a much higher risk of data loss. In short, it's a scenario that will eventually require a solution, if not a whole new way of storing and protecting data.

This makes sense to me; I just bought a 1.5 TB drive. I move large (video files) data files around on my systems all the time, so I can imagine that keeping a RAID array in synch with such massive size drives (especially when you consider the normal failure rates for drive sectors) is just getting harder and harder. I think th eonly answer at present is constant backups - local and offsite.

Here's Newman's summary of the problem - rebuilds are running into problems based on the hard error rate (something inherent to such technology):

What this means for you is that even for enterprise FC/SAS drives, the density is increasing faster than the hard error rate. This is especially true for enterprise SATA, where the density increased by a factor of about 375 over the last 15 years while the hard error rate improved only 10 times. This affects the RAID group, making it less reliable given the higher probability of hitting the hard error rate during a rebuild.

Doesn't sound like there's a real solution to this problem...

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