# Legacy batch — duration bands

Use with [Legacy batch: cron servers to Scheduler, Step Functions, and Batch](https://www.factualminds.com/blog/legacy-batch-job-modernization-eventbridge-scheduler/). One job. Checked 4 October 2026.

Classic Lambda stops at 900 seconds. Asynchronous invocations and event-source mappings on Lambda Managed Instances can run for 5,400 seconds, except Amazon MQ and Amazon DocumentDB. Multi-hour work is AWS Batch, not a longer function.

| Question | Answer |
| --- | --- |
| Job name and what the VM exists to do | |
| Duration of a normal run | |
| Band: under 900 seconds / up to 5,400 seconds async on LMI / multi-hour or array on Batch | |
| Dependencies held by Step Functions, or none | |
| File arrival is the trigger, or a clock is | |
| Is the handler one SDK call? If yes, use the Scheduler spoke instead | |

## Stop

- Rehosting the cron VM and calling it modernization.
- A second cron for "when the file shows up."
- Putting a one-call API wrapper in this estate. That is a different article.