Proposed Disk Array With 99.999% Availablity For 4 Years, Sans Maintenance

Thorfinn.au writes with this paper from four researchers (Jehan-François Pâris, Ahmed Amer, Darrell D. E. Long, and Thomas Schwarz, S. J.), with an interesting approach to long-term, fault-tolerant storage: As the prices of magnetic storage continue to decrease, the cost of replacing failed disks becomes increasingly dominated by the cost of the service call itself. We propose to eliminate these calls by building disk arrays that contain enough spare disks to operate without any human intervention during their whole lifetime. To evaluate the feasibility of this approach, we have simulated the behaviour of two-dimensional disk arrays with N parity disks and N(N – 1)/2 data disks under realistic failure and repair assumptions. Our conclusion is that having N(N + 1)/2 spare disks is more than enough to achieve a 99.999 percent probability of not losing data over four years. We observe that the same objectives cannot be reached with RAID level 6 organizations and would require RAID stripes that could tolerate triple disk failures.

Comments

I would love to, but that server is a soup Nazi

[jandrese]

So I tried to view the PDF, and it says "can't use the plugin, it causes problems on our server". So I figured I'd just download the file with wget instead. Nope, 403 forbidden.

Looks like fetch works though. If anybody else has trouble getting the file, try my local mirror.

Nothing novel is being proposed here

[fnj]

We observe that the same objectives cannot be reached with RAID level 6 organizations

Well, duh. RAID6 is not a serious level of redundancy. ZFS RAIDZ-3 (triple parity) FTW. And you can build in as many hot spares as you want. Dinosaurs who have still not adopted ZFS need to get a clue.