The Amazon EBS page states (which the author quotes):
> As an example, volumes that operate with 20 GB or less of modified data since their most recent Amazon EBS snapshot can expect an annual failure rate (AFR) of between 0.1% – 0.5%, where failure refers to a complete loss of the volume. This compares with commodity hard disks that will typically fail with an AFR of around 4%, making EBS volumes 10 times more reliable than typical commodity disk drives.
Nowhere within that does it say 0.00% failure rate, and later in the page they even describe how to mitigate the risk of losing data due to disk failure using snapshots, mirrored across availability zones.
> As an example, volumes that operate with 20 GB or less of modified data since their most recent Amazon EBS snapshot can expect an annual failure rate (AFR) of between 0.1% – 0.5%, where failure refers to a complete loss of the volume. This compares with commodity hard disks that will typically fail with an AFR of around 4%, making EBS volumes 10 times more reliable than typical commodity disk drives.
Nowhere within that does it say 0.00% failure rate, and later in the page they even describe how to mitigate the risk of losing data due to disk failure using snapshots, mirrored across availability zones.