Re: [SAGE] Long lived, cheap data storage

["Sam Johnston" <samj@samj.net>]

On 08/10/2007, Michael T. Halligan <michael@halligan.org> wrote:
> The problem here, is do you really want to keep all of your eggs in
> one basket? What happens in 3 years when Amazon realizes that they're
> not a storage company and shuts down EC2? Or when EC2 has an outage
> that causes data loss (like the one last weekend), and you're SOL
> because Amazon was never a storage company, and refused to provide an
> SLA?

We're talking about archiving here so were any of these things to
happen it would just be a case of finding an alternative; the
probability of Amazon's data centers and your house going away at the
same instant are overwhelmingly small (and indeed if this were ever
the case you would presumably have more to worry about!).

Regarding the EC2 outage in which "A software deployment caused
[their] management software to erroneously terminate a small number of
user's instances", the data referred to apparently relates to the
160Gb 'local' disk that is made available to you while your instance
is running in much the same way as a RAM drive would be - when the
instance goes away so does your data, which is why EC2 instances
typically back on to S3 for persistent storage. Some people are
pointing out that it is a beta service but even when in production
users should assume their instances are not indestructible (just as
you wouldn't store an important production database only in RAM
regardless of how reliable your hardware claimed to be). From the FAQ:

Q: What happens to my data when a system terminates?

The data stored on a specific instance persists only as long as that
instance is alive. You have several options to persist your data:

   1. Prior to terminating an instance, backup the data to persistent
storage, either over the Internet, or to Amazon S3.
   2. Run a redundant set of systems with replication of the data between them.

We recommend you should not rely on a single instance to provide
reliability for your data.

Sam (another happy AWS user)