Hi, Lukas
Many thanks , you are awesome. It's my fault that did not read the
documentation carefully.
I enlarged the "timeout queue". No 503 page returned, but the total
sessions in frontend accumulated quickly, which means most of the requests
are queued by haproxy.
I will try to add more servers to run backend server.
谢谢
金杰 (Jie Jin)
On Tue, Jul 1, 2014 at 9:50 PM, Lukas Tribus <luky...@hotmail.com> wrote:
> Hi,
>
>
>
>
> > I add an option maxconn after keyword server. When haproxy face
> > high volume of requests (about 20000 concurrent requests), it return
> > many 503 page
>
> Of course it will.
>
> You would like to serve 20000 concurrent requests, but your 6 servers
> only support 180 concurrent connections each. Do the math:
>
> 6 x 180 = 1080 concurrent request can be served in your configuration,
> of course you will see a lot of 503 errors.
>
>
>
> > why did haproxy send 503 page?
>
> Because all backend servers are busy serving 180 concurrent requests,
> as per your configuration. You have instructed HAProxy not the send
> more than 180 request per server, and that is exactly what HAProxy
> is doing (queueing the request until timeout queue [2] expires and
> then sending 503 errors).
>
>
>
> > I also did not understand the meaning of optioin maxconn. If I remove
> > this option, haproxy will return only very few 503 page.
>
> Please read the documentation about maxconn fully [1] then.
>
>
>
> > Do option maxconn in above configration mean: if concurrent requests
> > come from frontend is bigger than 180, haproxy will reject these
> > requests and return 503?
>
> It means: each server can handle up to 180 concurrent requests and HAproxy
> will not send more request to the server, but either use a different server
> (if there are), or queue it until "timeout queue" [2] expires, or
> "contimeout" as it is in your case (3 seconds).
>
>
>
> > If yes, can I configure the size of the queue?
>
> 180 *is* your per server queue size, and its exactly the limitation
> you are hitting.
>
>
>
> > Additional info
> > [jj@p2p3 tmp]$ echo "show errors" | sudo socat stdio /tmp/haproxysock
> > Total events captured on [01/Jul/2014:18:49:29.713] : 0
>
> You gonna need to configure the stats socket properly, "show errors"
> requires operator or admin privileges on the socket [2] ("level admin").
>
>
>
>
>
> Regards,
>
> Lukas
>
>
>
> [1]
> http://cbonte.github.io/haproxy-dconv/configuration-1.5.html#maxconn%20%28Server%20and%20default-server%20options%29
> [2]
> http://cbonte.github.io/haproxy-dconv/configuration-1.5.html#timeout%20queue
> [3]
> http://cbonte.github.io/haproxy-dconv/configuration-1.5.html#9.2-show%20errors
>
