Mpm prefork and http2 warning

RT Users
1

In RT5 documentation, it is stated that RT only works with MPM prefork.
However, when starting apache with mpm prefork, there is a warning:

AH10034: The mpm module (prefork.c) is not supported by mod_http2. The mpm determines how things are processed in your server. HTTP/2 has more demands in this regard and the currently selected mpm will just not do. This is an advisory warning. Your server will continue to work, but the HTTP/2 protocol will be inactive.

Disabling support for mpm prefork appears to be effected by Apache about 7 years ago so I am wondering if the RT5 documentation is still correct or does RT5 support the use of MPM event currently?

2

The documentation is correct. RT does not currently use or need HTTP/2, so unless you need it for other things you are running with the same Apache, you can safely disable it. We have experimented with running with the event mpm, and as noted in the docs, it seems OK under no load. But with any traffic, the event threads don’t route requests to RT processes well, and in the worst cases RT will become unresponsive. Until we can track this down, prefork running with mod_fcgid is still the most stable configuration to run with.

1 Like