Can you expand on this a bit? "But you could measure actual shm use with diff values."
Thanks From: Jeff Trawick <traw...@gmail.com<mailto:traw...@gmail.com>> Reply-To: "users@httpd.apache.org<mailto:users@httpd.apache.org>" <users@httpd.apache.org<mailto:users@httpd.apache.org>> Date: Tuesday, August 20, 2013 5:13 PM To: "users@httpd.apache.org<mailto:users@httpd.apache.org>" <users@httpd.apache.org<mailto:users@httpd.apache.org>> Subject: Re: [users@httpd] What is the impact of setting ServerLimit higher than MaxClients? On Aug 20, 2013 5:05 PM, "Rose, John B" <jbr...@utk.edu<mailto:jbr...@utk.edu>> wrote: > > Thanks for replying. > > Yes, it is prefork MPM. > > Reading this in the Apache documentation … > > "Do not set the value of this directive any higher than what you might want > to set MaxClients to." > > It also says … > > "Special care must be taken when using this directive. If ServerLimit is set > to a value much higher than necessary, extra, unused shared memory will be > allocated" > > What is classified as "much higher?" > > Is there a negative (or positive) impact of any kind of, for example, setting > ServerLimit to 2000 and MaxClients to 512? Unclear what much higher means, especially on a modern machine. I'd be extremely surprised if 2000 has any noticeable impact. But you could measure actual shm use with diff values. > > http://httpd.apache.org/docs/2.2/mod/mpm_common.html#serverlimit > > Thanks > > > From: Jeff Trawick <traw...@gmail.com<mailto:traw...@gmail.com>> > Reply-To: "users@httpd.apache.org<mailto:users@httpd.apache.org>" > <users@httpd.apache.org<mailto:users@httpd.apache.org>> > Date: Tuesday, August 20, 2013 4:50 PM > To: "users@httpd.apache.org<mailto:users@httpd.apache.org>" > <users@httpd.apache.org<mailto:users@httpd.apache.org>> > Subject: Re: [users@httpd] What is the impact of setting ServerLimit higher > than MaxClients? > > On Aug 20, 2013 4:26 PM, "Rose, John B" > <jbr...@utk.edu<mailto:jbr...@utk.edu>> wrote: > > > > What is the impact of setting the ServerLimit to a value significantly more > > than your MaxClients value? Say with a MaxClients set to 512 and > > ServerLimit of 2000? > > > > Assuming prefork MPM: > > You can increase maxclients across graceful restart, up to serverlimit > > Threaded MPMs: comparing maxclients vs server limit doesn't work without also > accounting for threadsperchild > > > > >
