50% of Failed requests with load balance
r at roze.lv
Wed Nov 10 18:48:43 MSK 2010
> Complete requests: 1000
> Failed requests: 499
> (Connect: 0, Receive: 0, Length: 499, Exceptions: 0)
It's just the content-length error and nothing else - 'ab' kinda measures
only the first response and if the following requests differ in size its
considered as error - loadbalancing between 2 servers where <? phpinfo(); ?>
has different output will lead to ab showing that half requests have failed.
In general phpinfo() is kinda quite slow for testing - I would suggest to
test something more generic like <? echo 'hello world'; ?>
> If i try with a html or jpg file don't get fail requests. But the times
> don't improve with the 2 servers. If i does the test directly to port
> 8080 for each machine, i get 5-6 seg average, but if i does to nginx
> with load balance, i get 7-8 seg average. It's that reasonable?
First - its good to run 'ab' from different box than the webserver itself as
its quite a resource hog and can slow down the webserver itself (especially
if the box isnt very fast) and then compare the results.
Second - no matter how you look at it a loadbalancer is extra layer between
client and server so if each server can push 10 requests per second it
doesnt always mean you will see 20 req/sec speed from the balancer.
More information about the nginx