On Feb 17, 2010, at 2:29 PM, Dan Denton wrote:
On Wed, Feb 17, 2010 at 3:19 PM, Robert Hall <rfh...@berkeley.edu>
wrote:
On Feb 17, 2010, at 12:50 PM, Dan Denton wrote:
On Wed, Feb 17, 2010 at 2:26 PM, Robert Hall <rfh...@berkeley.edu>
wrote:
On Feb 17, 2010, at 12:06 PM, Dan Denton wrote:
On Mon, Feb 15, 2010 at 12:53 PM, Robert Hall
<rfh...@berkeley.edu>
wrote:
Dan,
On Feb 15, 2010, at 10:37 AM, Dan Denton wrote:
Hello all. I’m trying to load test a login page served by
tomcat 6,
proxied through apache 2 with mod_proxy. I’m using JMeter
2.3.4 to
conduct the testing. My thread group consists of 500
sessions , and
the sample is a GET of a simple login page.
JMeter returns errors for a varying percentage of the samples.
The
errors returned are generally the following:
at
org
.apache
.jmeter
.protocol
.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1037)
at
org
.apache
.jmeter
.protocol
.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1023)
at
org
.apache
.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:
346)
at
org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:
243)
at java.lang.Thread.run(Unknown Source)
The issues I’m having are twofold. I’m having difficulty
determining
if these errors are coming from JMeter or Tomcat, as they’re
displayed
in the response window of JMeter. The developers think the
error is
coming from JMeter given the last few lines of the trace above.
The developers are correct.
Given that I'm not a programmer I should probably take their
word for
it,
but why would JMeter show this error as the response?
The system you are running JMeter on isn't able to handle the
load.
Second, I've tried tweaking my process counts (startservers,
maxspare,
etc...) with no change in the outcome. I can mitigate the
issue by
pointing JMeter directly to tomcat, but I need this product to
go
through our apache proxy for SSL.
Any help on this would be greatly appreciated.
There must be some JMeter setting that will work otherwise you
would be
unable
to access the webapp over SSL from the system that is hosting
JMeter.
Try reducing everything to a count of 1 in JMeter.
If that doesn't work, there is a problem with the SSL config in
JMeter;
google "jmeter ssl".
Otherwise, try spreading the load our across several JMeter
instances
installed on separate systems.
- Robert
Thanks for the reply Robert. I've set up JMeter 4 slaves, each
with at
least two 2.8 Ghz procs and 2 GB of RAM, and still regardless of
whether it's 1 node simulating 400 sessions or 4 nodes each
simulating
100, I still see these errors at 400 sessions or more. Also,
when I
use multiple slaves to execute the test, the percentage of
failures
when simulating 400 sessions is greater and the failures happen
earlier in the test.
This makes me think that this isn't just an issue with the systems
running JMeter, but I'm not sure. I've tried tweaking my SSL
Session
Timeout as well, but with no effect. I did this because watching
the
mod_status page on this apache instance, I can see the current
session
count top out at about 330 every time, then subside. My guess
was that
SSL sessions were somehow bottlenecking.
If anyone has any other suggestions, they would be greatly
appreciated.
Dan, this sounds like an Apache httpd configuration issue.
Check the values for the 'KeepAliveTimeout' and 'KeepAlive'
directives,
http://httpd.apache.org/docs/2.0/mod/core.html#keepalive
I suggest using "KeepAlive On" and "KeepAliveTimeout 1"; the
latter is
probably defaulted to 15.
- Robert
Thanks again Robert. My apache proxy has both directives already
set,
and KeepAliveTimeout was indeed set to 15. I tried running the 400
session test across 4 slaves with KeepAliveTimout set to 1 and 30,
and
the same result. A failure rate of approximately 20 percent.
Are there any other directives you suggest changing?
Thanks...
Surprising that KeepAliveTimeout of 1 and 30 produced the same
results.
Other directives: (with KeepAliveTimeout of 1)
MaxKeepAliveRequests - defaults to 100, try raising to 500
Separately, set KeepAlive Off.
Have you looked at the httpd error logs?
- Robert
Robert,
With KeepAliveTimout set to 1, and with MaxKeepAliveRequests set to
either 100 or 500, the same results. When using 4 nodes, 100 sessions
a piece, failure rates are between 10 and 30%. With individual nodes
firing off 400 sessions, failure rates are 10% or less.
With KeepAlive off, the same results. The results are somewhat random,
but around the same failure rates.
Nothing in the error logs that seems to point to this issue. Only
occasional messages regarding child processes during the restarts for
the configuration changes.
So far, none of these changes seem to have had an effect. The failure
rates are the same regardless.
Thanks for the help...
Is there a firewall in play? If so, I suggest turning it off and
retesting.
- Robert
---------------------------------------------------------------------
The official User-To-User support forum of the Apache HTTP Server Project.
See <URL:http://httpd.apache.org/userslist.html> for more info.
To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org
" from the digest: users-digest-unsubscr...@httpd.apache.org
For additional commands, e-mail: users-h...@httpd.apache.org
