hi, Just checking if someone has any pointers. Please let me know
Thanks, Vikram On Tue, Jan 22, 2013 at 3:37 AM, Vikram Nayak <[email protected]>wrote: > hi, > > I saw > http://stackoverflow.com/questions/8750518/difference-between-global-maxconn-and-server-maxconn-haproxyand > that clarifies a lot of my doubts. But there is still some confusion > whenever I look at haproxy-status. Please see if you can comment on the > below. Or if there is a document which explains this, please point me to > that. > > We are running a decent sized site. The config is slightly complicated so > let me just take a relevant subset. > > There is a service which is handled by around 5 backend machines which are > running apache. The apache server-status on those machines generally shows > 200reqs/sec and around 200 child processes would be busy. So "ps -ef | grep > httpd | wc -l" would give around 200. This is the prefork mode of apache. > > What confuses me is what frontend of haproxy-status shows. Let us just > focus on "Cur" values of "session rate" and "sessions". Here are the points > 1. Invariably, for the frontend, the cur-sessions is almost 4-5 times the > cur-sessionrate. Does this mean on an average a session is open by frontend > with the client for 4-5 seconds? It seems pretty high to me. Is this > governed by some configuration? > > 2. Now if I look at the backend and look at any of the 5 machines, I see > that cur-sessions is almost the same as cur-sessionrate and they both are > quite close to what apache server-status mentions as reqs/secs. So that > seems to pass the gut check. The question now is if the backend servers > seem to keep a session for 1 sec, why is the frontend keeping it for > 4-5seconds? > > 3. Lastly, I think this is outside the scope of HAProxy. But please advise > if you are aware : I am pretty sure that the requests hitting backend > apache are processed within 20-30milliseconds each. Each request returns a > response which is a decently big xml file - around 20-30KB. The question > now is why are 200 workers in apache busy (as per server-status) ? It > implies there are 200 concurrent connections but then the processing will > get over inside 20-30 milliseconds. So what are they doing for 1 second? > Are they waiting till the 20-30KB XML file gets transferred via HAproxy to > user's browser? Is there a way to free them up and let HAproxy take care of > the transfer? > > Will be great if you can give some advice. We are running 1.4.20 on a > Fedora 64-bit box. > > Thanks, > Vikram >
