Why are my Google AppEngine instances crashing with 'error code 121'?

Question

I have been running a java high-replication web application on Google AppEngine for some time now. About two days ago - basically out of nowhere - a lot of requests began to fai

Answer 1

Check your log retention limits, and that you haven't exceeded them. You wouldn't expect that bypassing your log retention limits would cause an exception that caused the instance to fail, but after I increased mine, I stopped seeing this error crop up and my backend cron jobs were able to complete.