Ok, so we have several instances on several nodes in a clustered environment. One of them is for JD Edwards stuff and has had an issue lately with a job failing because there was not space in the tempdb to complete it. The code for this job hasn't changed in YEARS, and yet I realize the data size may have.

Anyway, after setting the tempdb to some Autogrowth that wouldn't bork that drive I started digging deeper on this install. It seems there are some scheduled jobs that are switching the recovery mode back and forth from Simple to Full with backups supposed to be happening around those for some reason. I believe this is what caused the T-Logs backup to fail at some point and thus not have enough room for the tempdb itself to complete these long-standing JDE jobs.

So questions:

1. Am I totally ignorant to think that switching back and forth from Simple to Full is a bad idea on a regular basis?
2. If I am right that this is a bad idea what other scenarios other than the one I have already described can I use to illustrate this to my Sr. DBA who must have created this situation?

TIA