[Catalyst] Requirements for Catalyst

Scott McWhirter scott+catalyst at konobi.co.uk
Tue Feb 24 21:56:31 GMT 2009


On Tue, Feb 24, 2009 at 13:38, Jason Kohles <email at jasonkohles.com> wrote:
> EC2 has persistent storage now (now meaning as of last April), so you can
> have volumes on your hosts that are backed by S3, so you don't lose your
> data when the instance goes away.

EBS volumes aren't backed on S3. They are simply persistent block
devices (run on NAS storage) that you can attach and detach from EC2
instances. However, you can "snapshot" the volume and these snapshots
are stored on S3. The benefit to snapshots is that the snapshots are
incremental backups (only store what has changed since the last
snapshot) and they are stored compressed. To re-initialize a snapshot,
you can simply create a new EBS volume based on a snapshot.

Also important to note is that with EBS volumes, you get charged based
on IO requests as well as the storage space used by the size of the
volume (ie: you have a volume of 180Gb, you get charges for 180Gb of
storage even if you have nothing on it).

> Ultimately though, if you don't need the flexibility of EC2 and are planning
> to just have one host running 24/7, then EC2 is roughly the same price as
> just getting a colocated server somewhere.

For a small instance it's about $75 a month on average to run
(instance hours charges). A large instance is about $300 a month. If
you want to run a database server, i recommend backing onto an EBS
volume and running a "large" instance... there are some serious
problems with IO performance on the "small" ec2 instances.

ta!


-- 
-Scott McWhirter- | -konobi-
[ Technology Consultant - Cloudtone Studios ]



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