As of late I'm seeing a lot of AH01179: balancer slotmem_create failed
error messages which prevent apache2 from starting. I do have DefaultRuntimeDir /var/run/apache2 set. For some reasons there appear to be "left-over" .shm files in the DefaultRunTimeDir between stop-starts/restarts which then get picked up by mod_slotmem when mod_proxy asks it for shared memory. Unfortunately, those .shm files sometimes have the wrong size and get rejected by the mod_slotmem code due to size mismatch. To me it looks like this situation suffers from the same issue as reported in https://issues.apache.org/bugzilla/show_bug.cgi?id=55449 though I only have one user (nobody) for all the worker processes. I get the systems back up and running by deleting all .shm files in the DefaultRunTimeDir between stop-starts/restarts but this seems fragile to me. Another workaround, as crude as it is, seems to be disabling the reusing of existing shared memory segments by setting fbased = 0; in modules/slotmem/mod_slotmem_shm.c in slotmem_create(). Neither of those two appraoches seems "right" to me. I do need at least a temporary workaround since this is causing major havoc.
