Why does df say my EFS disk has a capacity of 8 Exabytes?

Solution 1:

EFS claims it can store "petabytes of data", expanding automatically. AWS has likely decided that 8 exabytes is the number they want to present to the operating system as free space. I can't see any advantage to presenting a smaller number, as some software wants to know free space available on a disk.

From the FAQ

Q. How much data can I store?

Amazon EFS file systems can store petabytes of data. Amazon EFS file systems are elastic, and automatically grow and shrink as you add and remove files. You do not provision file system size up front, and you pay only for what you use.