What are the limitations of crontab?

Question

Hardware considerations aside, are there any limitations on:

1. The maximum number of cron jobs that can be scheduled for a single user
2. The maximum number of CONCURRENT jobs that can be scheduled for a single user?

Server is running Ubuntu 10.0.4 LTS

Additional info: The jobs will all be launching the same executable, but with different command line arguments

Answer 1

I don't know of a limit here - although there surely will be some - But I never hit one and I've seen rather huge crontabs.

Just give it a try and let us know!

Answer 2

For my part, I never saw any limit for Crontab.
However, I think the limit of your crontab is just the limit of your station. I mean the capability of the computer where you are running your OS.
You must test :
- the load of the unit
- the swap use
- how many processes for each daemon or exec.

Example :

If you are hosting a LAMP service with advanced services (like a big SQLDB), don't plan a huge dump (or tables cleanup ) when the LAMP is charged (find hours where the server have a low load).