RAM is the new hard drive

Like most websites, Hunch uses memcached a lot. The really interesting thing is that the data stored in them is basically as persistent as data written to disk: the machines have never gone down, lost power, or had memcached crash in roughly a year of use.

Hard drive MTBF is a few years in practice. So our memcached is already 20-25% as reliable as a traditional drive. We just need to build all the other things that traditional storage has that memcached lacks: RAIM (reliable arrays of inexpensive memcaches?), backup/restore, replication, etc.

Of course, the downside is that a terabyte of RAM still costs something like $60,000. But that price is going down and I'm not sure that the datasets behind many websites are really that big. For example, Wikipedia is only a little over a terabyte.