[squid-dev] [RFC] CRUSH peer selection method

[Loic Dachary]

Hi Alex,

On 04/17/2017 06:28 PM, Alex Rousskov wrote:
> On 04/17/2017 09:08 AM, Loic Dachary wrote:
> 
>>   peer 1 targeted by a set of requests (X1)
>>   peer 2 targeted by a set of requests (X2)
> 
>> and we add a new peer, CRUSH makes it so 1/3 of the requests from peer 1 and 2 move to peer 3
> 
>>   peer 1 targeted by a set of requests (2/3 of X1)
>>   peer 2 targeted by a set of requests (2/3 of X2)
>>   peer 3 targeted by a set of requests (1/3 of X1 + 1/3 of X2)
> 
> How would the last three lines look for CARP and sourcehash?

I'm not sure :-) But I could write a simulation to figure it out. Unless I missed a part of src/carp.cc that mitigates the problem, the situation should not be very different from what is described at https://docs.openstack.org/developer/swift/ring_background.html#part-2

> 
> 
> Thank you,
> 
> Alex.
> P.S. For the record, this is
>      http://bugs.squid-cache.org/show_bug.cgi?id=4704

Thanks for adding the link and sorry for the confusion. I should have posted to the list only instead of both.

Cheers

-- 
Loïc Dachary, Artisan Logiciel Libre