A few weeks back, we've noticed our snapshot bills to grow weirdly high.. after some debugging, I've found the snapshot billing and way snapshots stored as an interesting concept..
As the graph says, the usage vs snapshot billing isn't growing proportionally linear.. (1/n)
I decided to debug how snapshots are billed.. fundamentally, snapshots are block-level backups of EBS volumes.. since AWS can't see data inside your block, they read disk blocks occupied and take a copy of them and store them as objects in their s3.. (2/n)
Every time there's a data change inside your EBS volume, by nature of linux and hard disks, the new blocks is where data is written.. So, AWS knows there's change of data (this could be deletion of data too) and marks those blocks as the difference in data..thus incremental (3/n)