On 02/18/2011 02:42 PM, Fran Boon wrote:
On 18 February 2011 20:19, Filip Hanik - Dev Lists<devli...@hanik.com> wrote:
Simplest to try first is the disablereuse flag
http://httpd.apache.org/docs/2.2/mod/mod_proxy.html
disablereuse On
and if that solves the problem, you know that the problem with not enough
threads on tomcat.
(Could be from stale connections that are still holding a thread)
Awesome - that makes it at least 10x more reliable!
Still not perfect, but a massive improvement.
Yes, it is also useful if you have more web servers than you have
application servers.
Any more suggestions on what I can do to clear the last errors&
generally how to approach this configuration?
What errors? I'm not sure what you are referring too here?
Since you've made changes to your environment, you may want to post more
detail on what is going on now.
(Apache& Tomcat on the same physical server. Load isn't terribly high
right now, but I'd like it to be able to scale. There is 2Gb RAM
available (although this is shared with PostgreSQL which is tuned to
think it has 1024 available for it)
If they are on the same servers, I would leave the "disablereuse On" as
the cost of a connection establishment is not as high as it would be
over a network.
Plan to scale out, meaning, as one box gets high in utilization, you
should be able to add another box with another httpd/tomcat combo to
balance your load.
It requires some sort of load balancer in front of your web servers.
(for software, I would look into http://haproxy.1wt.eu/)
If your database gets saturated, you may want to look into data caching
solutions, to lower the number of trips to the database. there are
plenty of such solutions out there. In the extreme case, you'd get rid
of the database and move to a distributed NoSQL solution.
best
Filip
Many thanks :)
Fran.
Filip
On 02/18/2011 12:24 PM, Fran Boon wrote:
httpd error log:
client denied by server configuration:
proxy:ajp://localhost:8009/geoserver/gwc/service/wms
This happens under 'high' load only: 1st few requests of a batch are
answered but then they start dying - there are no bad URLs here.
httpd snippet:
ProxyPreserveHost on
RewriteRule ^/geoserver/(.*)$ ajp://localhost:8009/geoserver/$1 [P]
ProxyPassReverse /geoserver ajp://localhost:8009/geoserver/
<LocationMatch "^(/[\w_]*/geoserver/.*)">
Order Allow,Deny
Allow from all
</LocationMatch>
I have tried these configuration options without any apparent difference:
<Proxy ajp://localhost:8009>
ProxySet keepalive=On timeout=15 ttl=60
</Proxy>
Happens even with 'Allow from all' in proxy.conf (in fact nothing in
that file makes any difference, presumably as it only affects Forward
proxies.
I have tried with both the default prefork MPM& also the worker MPM.
Back-end is GeoServer in Tomcat 6 (exactly same thing happened with
5.5) on Debian Squeeze 64-bit& current Sun JVM.
Nothing in the logs at the back-end, though, seems to be a problem
with the Connector.
Same thing whether or not using the 'APR based Apache Tomcat Native
library 1.1.20' or not.
I tried putting in a connectionTimeout into server.xml, but it makes
no difference:
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443"
connectionTimeout="60000" />
Same with setting the minSpareThreads="32" maxThreads="256"
to match those in apache.conf
<IfModule mpm_worker_module>
StartServers 2
MaxClients 256
MinSpareThreads 32
MaxSpareThreads 128
ThreadsPerChild 32
MaxRequestsPerChild 1024
</IfModule>
None of these tuning options seem to make much difference.
Only web posts I've seen are the on/off conditions rather than erratic
ones.
Many thanks, for any suggestions :)
Fran.
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