Nginx HTTP Server - Fourth Edition

Degradation

The HTTP Degradation module configures your server to return an error page when your server runs low on memory. It works by defining a memory amount that is to be considered low, and then specifying the locations for which you wish to enable the degradation check:

degradation sbrk=500m; # to be inserted at the http block level 
degrade 204; # in a location block, specify the error code (204 or 444) to return in case the server condition has degraded