Quota issues - Data usage jumped to 100%

[Connor Dunn]

My app has been growing slowly over a couple of years and is around 70% of the free datastore usage allowed, today however it jumped to 100% and I'm getting quota denials. It did this before and I enabled billing, which fixed the problem, but after a few days the usage dropped down to 70% again.

In the billing history I was never billed for the quota being over 100% (despite it showing as over 100% in the dashboard. This meant according to the billing history I never needed more than the free quota, but I had to enable billing and pay the minimum billing amount for my app to keep running (rather annoying). After this seemed to go away I disabled billing, but now, some time later it's happened again.

I have again enabled billing as I want my app to function, but I was wondering what was going on here, is it a bug or is something happening that I don't understand?

Thanks