You mean availability zone. Well I guess me, Reddit, Foursquare, and plenty of other sites just got lucky in the bad availability zone.

Ah yes, here's the classic AWS apologist pattern in full effect. You don't use EBS! Of course you don't, you would have to be some kind of friggin' idiot to use EBS. So what do you use for, say, MongoDB data files, that is different from morons like me who stupidly assumed they could/should use EBS?

We use EBS, and had machines in the availability zone that went down that were affected. Those machines were out for longer than a day, but we were back up within an hour because we had redundancies built in across other availability zones.

If you're doing anything that matters, you can't rely on a single zone/machine/whatever, no matter who your hosting provider is.

So you're saying we need a cloud of clouds?

Just a higher level of abstraction. Many people don't want to care about what zone they're running in, or really anything about the machine (or even virtual machine) they're running on; they just want to run their apps "somewhere" that persists through hardware problems. Maintaining such a thing isn't Amazon's charter, though; it's more the job of a cloud application hosting provider, like Heroku (who I'm surprised isn't multi-homing their apps on several clouds by now for just this reason.)

Sounds like a certain exotic financial instrument...

Only fools would want a persistent filesystem for their OS! </sarcasm>

How is S3 not persistent...

Notice I said for the OS. From Wikipedia:

"An EC2 instance may be launched with a choice of two types of storage for its boot disk or "root device". The first option is a local "instance-store" disk as a root device (originally the only choice). The second option is to use an EBS volume as a root device.

Instance-store volumes are temporary storage, which survive rebooting an EC2 instance, but when the instance is terminated (e.g., by an API call, or due to a failure), this store is lost." (Emphasis mine)

Most choose the EBS type of instance now, because having the OS on a persistent storage device is more convenient for typical server scenarios (as you might imagine).

http://en.wikipedia.org/wiki/Amazon_Elastic_Compute_Cloud#Pe...

The only scenario I can see that would require hitting an EBS store often enough to matter would be if you put your database on it. Obviously your OS kernel is going to be in resident memory, so your argument is somewhat of a strawman.

It's the root device that's on EBS. On most AMIs with EBS root that's the entire OS i.e., /etc, /dev, /bin, /usr, etc. and not just the OS kernel.

And for the things that matter (i.e., not fake mount points) that will all mostly live in resident memory.

... and your point is?

How would you run your database off a file storage service?

SimpleDB latency is bad, but not that bad.

I doubt you'll be able to do much better with another scalable storage system (that's freely available).