[karmakaze]

They mention both flash and disk, which finally gets explained as tiers 2 and 3. Also less clear though I assume this applies to their hosted service offering and not the core software.

> "We can take the lesser-used data that hasn't been touched in a while and shuttle it off to flash where it can sit for a while. When the user comes back eventually, it's very easy for us to seamlessly move it from flash back into memory. And that allows the company to save costs," he said.

> Redis is now planning to extend the concept to disk-based memory to offer support for a three-tiered architecture.

[SteveNuts]

I would like at least two more tiers: S3, and an LTO tape drive.

[b112]

What about the stenographer tier? A simple terminal, a little transcription, and I bet we'd keep restore delay down under a few seconds + 5 minute file lookup of stored paperwork.