[Mongrel] load balancers and mongrel
luislavena at gmail.com
Fri Oct 26 20:46:59 EDT 2007
On 10/26/07, Andrew Arrow <andrew at geni.com> wrote:
> We have a load balancer sending requests to one of X boxes and one of
> N mongrel processes on that box.
> Since each mongrel processes is multi-threaded but it has a mutex
> around the section that calls rails, we end up with several requests
> queued up waiting when they could have gone to another box with a
> free process.
> For example, boxA, and boxB.
> boxA has mongrels 1 through 10
> boxB has mongrels 11 through 20
> Load balancer sends a request to boxA mongrel 5.
> Load balancer sends a request to boxB mongrel 12.
> Load balancer sends a request to boxA mongrel 5 again.
> It has to wait for the 1st request still running on boxA mongrel 5.
> How can we help the load balancer know it should have sent the
> request to any number of other free mongrels vs. queuing up threads
> that have to wait?
That's the bad logic of your balancer.
If it's a hardware one, check if there are some algorithms you can tweak.
For a software-based one, check the configuration file if there is
some param about spreading / distributing the requests.
Also, could be helpful if you mix the box A and box B list of members
for the cluster:
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which is the price which all of us must pay to achieve any goal that
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