nines

Just so everyone is aware, S3 guarantees only 4 nines of relability (99.99% uptime), not 5 nines.

Are you sure you didn't mean a few (about 10) nines somewhere?

And without process linking and supervision, which helps systems built using Erlang/OTP achieve nine nines of uptime.

And often too much importance is placed in hitting five nines of availability.

The front fork on your bike is almost certainly not six-nines reliable.

Unfortunately, currently we probably make do with a few less nines on all these items.

I even ran a 5 nines 9-1-1 service off Asterisk, as embarrassing as that is.

If I can dial that data loss potential in a robust way, I'll take the 5 nines of 100x write capability.

In other words, you can only get so many reliability nines and still be profitable for mass transport (as opposed to, for example, Space Shuttle).

Five nines would be one error per store per year.

Six nines would be one error per store per _decade_.

Yet it works with way over five nines confidence.

And would a spectacular seeming "six nines" of reliability, which means dropping a thousand mails/adviews/updates/orders _per hour_ be acceptable?

This is in fact where the "nine nines" reliability comes from- restarting nodes extremely quickly after runtime errors.

This is how Erlang (for example) gets its reputation of being "nine-nines" capable (i.e.

The potentially extreme fault tolerance ("nine nines" is not unheard-of), and things like hot code deployment, appeals to me as a web developer.

All went lame; all blind; Drunk with fatigue; deaf even to the hoots Of tired, outstripped Five-Nines that dropped behind.