fair load balancing?

Moses Hohman moses at collaborativedrug.com
Mon Jun 23 23:04:06 UTC 2008

On Jun 23, 2008, at 3:49 PM, Ryan Woodrum wrote:

> Hmmm.  I'm not so sure.  And before I go further, please someone  
> correct me if I'm way off base because I haven't looked at the code  
> in awhile.  Perlbal knows when it has shuttled a request to a  
> backend and it also knows when that request has been completed.  For  
> this reason, it's not going to send multiple requests to the same  
> backend.  (Is that correct?)  Operating under the assumption that  
> perlbal is the only client to your backends, you should never end up  
> waiting for them (unless the entire pool is busy).  Now... if  
> something is a client to your backend other than perlbal, all bets  
> are off.

 From what I can tell, that's not the case. Perlbal does not keep  
track of whether the request is done, and happily queues up requests  
on any of its backends that it has verified. Basically, it assumes the  
backends can handle concurrent requests, which is usually a fine  
assumption, just not with Rails.


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