[hueving]

>Except that most cloud providers offer replication and load balancing, integrated directly into their other products already. They spent a lot of time making sure that it works so you don't have to.

Have you ever used EC2 with traditional apps hoisted onto the cloud? Just because you can click a button for ELB doesn't mean anything when the system wasn't horizontally scalable to begin with. EC2 is just VMs, it doesn't provide any high availability at the VM level.

With local solutions (e.g. vmware/kvm/openstack), you can live migrate these annoying (but critical) pets around as you phase out hardware with very limited traffic interruption. With EC2, the thing eventually just shits the bed and you get a notice saying the instance will be retired even though it's already in a worthless state.