Are Lambda timeouts an issue?

[astrostl]

Snapshots of busy volumes may take long time. If you have a lot of (or) busy volumes - don't use Lambda. Maximum timeout for Lambda is 300s and there's currently no way to disable or confgure retry on error (if you know - let me know, please).

When calling for a snap via aws ec2 create-snapshot --volume-id, the API immediately returns a JSON document and proceeds with a snapshot in the background. Is the concern on 300s someone having so many volumes that even this process would take too long, or is it actually waiting for the snapshot to complete?