[stephengillie]

> GCP will transparently migrate the VM while it is running for you. You never see it, you customers don't either.

This is just hot-migration between hosts. It "stuns" a VM for a fraction of a second - very high performance databases and videogame servers will sometimes notice, while everything else just sees a spot of lag and keeps going.

AWS are an odd cloud vendor who don't support many common cloud features:

- No hot migrate between hosts.

- No hot-add RAM or CPU.

- No memory-state snapshot, only disk snapshot.

- No arbitrary CPU or RAM quantities, only "t-shirt" sizes - can't build servers in "nonsensical" configurations like 12 CPUs and 1GB RAM, or 1 CPU and 128 GB RAM.

This is on top of having arbitrary separators in their data centers, so they send you strange messages about having to delete and rebuild your servers in the same data center. AWS may think it's cute to sell different "areas" in their data center, but the way to have redundancy for servers in AWS us-east-1 is to have servers Azure US West 2 or GCP us-central-1.

Like early iOS in the smartphone space, AWS are dominant in the VM space through marketing, not features.

[cthalupa]

>AWS may think it's cute to sell different "areas" in their data center

https://aws.amazon.com/about-aws/global-infrastructure/

From re:invent presentations, we know that even availability zones might be made up of multiple datacenters. In 2014, James Hamilton's presentation said that one of the AZs in us-east-1 had 6 separate datacenters.

I don't think it's really accurate to say AWS is selling us different 'areas of a datacenter' when we know that AZs are not only not sharing a datacenter, but might be multiple datacenters themselves.

[stephengillie]

From a certain point of view, it's Amazon using different terminology - what others call a data center, they call an AZ...or even a subset of an AZ, and we'll never know exactly - nor the capacity of each[0]. And what they call a data center, others call a region.

[0] When a server class is "sold out" in a region, you can't start your server - but there's no indication of this anywhere until you try to start your server. Other cloud providers auto-rebalance VMs to make space - using AWS is sometimes more like using physical servers than VMs - maybe moreso with paravirtualization.

[cthalupa]

I'm really confused as to what you're trying to say.

AWS has been very open over the years about what their terminology means. When they say datacenter, they mean it in the traditional sense of the word. When they say an AZ is made up of at least one but sometimes multiple datacenters, they mean that that an AZ has multiple physical datacenters. They're not slicing up a server room and calling these multiple datacenters.

We also know that AZs are physically separated from each other.

So an AWS region has at least as many physical datacenters as it has AZs, and potentially quite a few more.

James Hamilton has talked pretty extensively about this stuff at re:invent, and as an AWS customer, his talks have been some of the most interesting to me.

Other people calling a datacenter a region doesn't suddenly reduce an AWS region down to a datacenter. A datacenter is a word with a pretty specific definition, and an AWS region does not fit that definition.

[stephengillie]

The confusion is entirely mine. Your clarity is appreciated.

[cthalupa]

You're welcome!

My apologies if I came across as combative.