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Posted to users@httpd.apache.org by DhilliPrasad Nellepalli <nd...@gmail.com> on 2017/09/15 13:44:02 UTC
[users@httpd] Increasing packet size to 64 KB on mod_proxy and mod_proxy_balancer
Hi All,
We are using apache mod_proxy and mod_proxy_balancer to talk to the backend
ratpack.io app (which has netty by default).
We see high latency when the headers go above 8 KB. to debug the issue we
have monitored the traffic from apache to netty with wireshark.
We noticed that apache is sending request in multiple packets to netty.
This is adding latency in processing the request.
Is there a way to increase the packet size to higher value like 64 KB in
mod_proxy. I know this can be achieved with modJK and AJP. But I don't
believe netty supports AJP.
We are running out of options in solving the issue.
Any help will be much appreciated.
Thanks,
-Dhilli
Re: [users@httpd] Increasing packet size to 64 KB on mod_proxy and mod_proxy_balancer
Posted by Yann Ylavic <yl...@gmail.com>.
On Wed, Sep 20, 2017 at 2:54 AM, DhilliPrasad Nellepalli
<nd...@gmail.com> wrote:
>
> We don't use the ssl from apache to netty. One thing I have notice was
> expect:100-Continue header in the request to apache.
That's the request (of the Apache proxy) to the backend, right?
If so...
> Not sure if except
> header has anything to do with the fragmentation to send the headers first
> and wait for response and then send the body.
.. clearly, the proxy has to wait for an "ack" (HTTP/1.1 100 Continue)
from the backend to send further data (after the header), that's how
100-continue works.
But if "Expect: 100-continue" is sent by the proxy it means that you
confifured it (i.e. ProxyPass ... ping=... ).
Is it the case?
Regards,
Yann.
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Re: [users@httpd] Increasing packet size to 64 KB on mod_proxy and mod_proxy_balancer
Posted by DhilliPrasad Nellepalli <nd...@gmail.com>.
Thanka Yann.
We don't use the ssl from apache to netty. One thing I have notice was
expect:100-Continue header in the request to apache. Not sure if except
header has anything to do with the fragmentation to send the headers first
and wait for response and then send the body.
Regards,
-Dhilli
On Sep 16, 2017 3:39 PM, "Yann Ylavic" <yl...@gmail.com> wrote:
Hi Dhilli,
On Fri, Sep 15, 2017 at 3:44 PM, DhilliPrasad Nellepalli
<nd...@gmail.com> wrote:
>
> We see high latency when the headers go above 8 KB. to debug the issue we
> have monitored the traffic from apache to netty with wireshark.
>
> We noticed that apache is sending request in multiple packets to netty.
This
> is adding latency in processing the request.
mod_prox_http sends the HTTP header (all the headers) in a one go,
although some filters in the chain may "fragment" it (like mod_ssl,
but that'd be 16K packets per TLS record size max).
>
> Is there a way to increase the packet size to higher value like 64 KB in
> mod_proxy. I know this can be achieved with modJK and AJP. But I don't
> believe netty supports AJP.
>
> We are running out of options in solving the issue.
It looks more like a limit on the system, TCP (send) buffers size?
This is not something that can be forced on the mod_proxy side (no
ProxySendBufferSize similar to SendBufferSize for the client
connection), but it can be tuned by default on the system.
Regards,
Yann.
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Re: [users@httpd] Increasing packet size to 64 KB on mod_proxy and mod_proxy_balancer
Posted by Yann Ylavic <yl...@gmail.com>.
Hi Dhilli,
On Fri, Sep 15, 2017 at 3:44 PM, DhilliPrasad Nellepalli
<nd...@gmail.com> wrote:
>
> We see high latency when the headers go above 8 KB. to debug the issue we
> have monitored the traffic from apache to netty with wireshark.
>
> We noticed that apache is sending request in multiple packets to netty. This
> is adding latency in processing the request.
mod_prox_http sends the HTTP header (all the headers) in a one go,
although some filters in the chain may "fragment" it (like mod_ssl,
but that'd be 16K packets per TLS record size max).
>
> Is there a way to increase the packet size to higher value like 64 KB in
> mod_proxy. I know this can be achieved with modJK and AJP. But I don't
> believe netty supports AJP.
>
> We are running out of options in solving the issue.
It looks more like a limit on the system, TCP (send) buffers size?
This is not something that can be forced on the mod_proxy side (no
ProxySendBufferSize similar to SendBufferSize for the client
connection), but it can be tuned by default on the system.
Regards,
Yann.
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