CODEWITHSUNDEEP
amazon-web-servicesamazon-s3
user6136315
user6136315

Reputation: 705

How AMI to S3 costs

We a script to create couple of AMI, On successful completion of AMI it deletes the old AMI. As of my understanding AWS only charges for the space we use in S3 for storing snapshot that was created by an AMI.

If I created two AMIs for an instance on different dates(those two AMIs create two different snapshots). will they charge for only new snapshot size? or for the two snapshots?

How AWS charges for this process?

Upvotes: 0

Views: 610

Answers (2)

John Rotenstein
John Rotenstein

Reputation: 269091

An Amazon Machine Image (AMI) is actually a standard EBS snapshot, with additional metadata.

EBS snapshots are incremental in nature, meaning that only blocks that have been added or changed are copied to Amazon S3.

This means that successive snapshots could incur very little additional cost. Imagine this scenario:

  • AMI 1 is created from an instance (or, more accurately, from the EBS volumes associated with the instance)
  • Some data is changed on the EBS volumes
  • AMI 2 is created from the instance

Since each AMI is a snapshot, and snapshots only copy incremental data to S3, then the additional cost for AMI 2 would only be the new/modified blocks.

If AMI 1 were then deleted, the cost drop would be minimal, since most blocks contained in the AMI 1 snapshot would be kept for the AMI 2 snapshot.

One interesting result of all this (which is merely my suspicion, since I could not find any official statement to this effect) is that, if your AMI is based off an existing volume (eg an AMI from Amazon), then any snapshots/AMIs created of that volume will actually inherit blocks that are part of the original snapshot. Therefore, you (probably) do not pay the full cost of storing that AMI since the snapshot points to blocks already in a snapshot originally created by Amazon. (Don't worry if you didn't understand all that!)

Upvotes: 2

Naveen Vijay
Naveen Vijay

Reputation: 16482

AMIs are stand alone in nature and treated individually no matter whether created out of the same instance on the same day. So they charges of the AMI storage would be calculated 2 times.

For the record the AMI creation involves the snapshotting behind the scenes and AWS performs those snapshots calculating the delta; so the AMI creation process would faster the second time but still they are treated a 2 individual copies.

Upvotes: 0

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