Q: How isolated are Availability Zones from one another?

Each Availability Zone runs on its own physically distinct, independent infrastructure, and is engineered to be highly reliable. Common points of failures like generators and cooling equipment are not shared across Availability Zones. Additionally, they are physically separate, such that even extremely uncommon disasters such as fires, tornados or flooding would only affect a single Availability Zone.

Q: Is Amazon EC2 running in more than one region?

Yes. Please refer to Regional Products and Services for more details of our product and service availability by region.

Q: How can I make sure that I am in the same Availability Zone as another developer?

We do not currently support the ability to coordinate launches into the same Availability Zone across AWS developer accounts. One Availability Zone name (for example, us-east-1a) in two AWS customer accounts may relate to different physical Availability Zones.

Q: If I transfer data between Availability Zones using public IP addresses, will I be charged twice for Regional Data Transfer (once because it’s across zones, and a second time because I’m using public IP addresses)?

No. Regional Data Transfer rates apply if at least one of the following is true, but is only charged once for a given instance even if both are true:

  • The other instance is in a different Availability Zone, regardless of which type of address is used.
  • Public or Elastic IP addresses are used, regardless of which Availability Zone the other instance is in.