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I've been naively setting up our distributed databases in separate AZs for a couple years now, paying, sometimes, thousands of dollars per month in data replica

I've been naively setting up our distributed databases in separate AZs for a couple years now, paying, sometimes, thousands of dollars per month in data replication bandwidth egress fees. As far as I can remember I've never never seen an AZ go down, and the only region that has gone down has been us-east-1.

cyounkins 5y ago
Is that separate AZs within the same region, or AZs across regions? I didn't think there were any bandwidth fees between AZs in the same region.
- TheP1000 5y ago
  That is incorrect. Cross az fees are steep.
- electroly 5y ago
  It's $0.01/GB for cross-AZ transfer within a region.
  - nemothekid 5y ago
    In reality it's more like $0.02/GB. You pay $0.01 on sending and $0.01 on receiving. I have no idea why ingress isn't free.
    - rfraile 5y ago
      Plus the support percentage, don’t forguet.
treis 5y ago
AZs definitely go down. It's usually due to a physical reason like fire or power issues.
maximilianroos 5y ago
> I've never never seen an AZ go down, and the only region that has gone down has been us-east-1. Doesn't the region going down mean that _all_ its AZs have gone down? Or is my mental model of this incorrect?
- urthor 5y ago
  No. See https://aws.amazon.com/about-aws/global-infrastructure/regions_az/ https://aws.amazon.com/about-aws/global-infrastructure/regio... A region is a networking paradigm. An AZ is a group of 2-6 data centers in the same city more or less. If a region goes down or is otherwise impacted, its AZs are unavailable or similar. If an AZ goes down, your VMs in said centers are disrupted in the most direct sense. It's the difference between loss of service and actual data loss.
wjossey 5y ago
There was an AZ outage in Oregon a couple months back. You should definitely go multi AZ without hesitation for production workloads for systems that should be highly available. You can easily lose a system permanently in a single AZ setup if it’s not ephemeral.

cyounkins 5y ago

Is that separate AZs within the same region, or AZs across regions? I didn't think there were any bandwidth fees between AZs in the same region.

TheP1000 5y ago
That is incorrect. Cross az fees are steep.
electroly 5y ago
It's $0.01/GB for cross-AZ transfer within a region.
- nemothekid 5y ago
  In reality it's more like $0.02/GB. You pay $0.01 on sending and $0.01 on receiving. I have no idea why ingress isn't free.
  - rfraile 5y ago
    Plus the support percentage, don’t forguet.

treis 5y ago

AZs definitely go down. It's usually due to a physical reason like fire or power issues.

maximilianroos 5y ago

> I've never never seen an AZ go down, and the only region that has gone down has been us-east-1. Doesn't the region going down mean that _all_ its AZs have gone down? Or is my mental model of this incorrect?

urthor 5y ago
No. See https://aws.amazon.com/about-aws/global-infrastructure/regions_az/ https://aws.amazon.com/about-aws/global-infrastructure/regio... A region is a networking paradigm. An AZ is a group of 2-6 data centers in the same city more or less. If a region goes down or is otherwise impacted, its AZs are unavailable or similar. If an AZ goes down, your VMs in said centers are disrupted in the most direct sense. It's the difference between loss of service and actual data loss.

wjossey 5y ago

There was an AZ outage in Oregon a couple months back. You should definitely go multi AZ without hesitation for production workloads for systems that should be highly available. You can easily lose a system permanently in a single AZ setup if it’s not ephemeral.