Miles,
The weight is part of the consistent hash feature added to parent selection in
TS-2996. I suppose they
Did not wish to change the behavior of the round robin methods when consistent
has was added.
For round robin=true a client will always get the same parent. If the parent
cannot be reached,
It will be marked down and another will be selected from the parents list.
Thanks
John
jrushf...@apache.org
On 11/3/16, 11:47 AM, "Miles Libbey" <mlib...@gmail.com> wrote:
On Wed, Nov 2, 2016 at 10:40 AM, John Rushford <jjrushf...@gmail.com> wrote:
> Miles,
>
> The weight is only used for round_robin = consistent_hash. It is ignored
for all other strategies.
> In the consistent hash strategy, weight defaults to 1 and it’s a
multiplier to the number of replicas of
> A parent inserted alon the hash ring.
Is there a reason why it was only applied to consistent hash? I think
this is too complex to explain currently.
> Round_robin=true returns a parent from an array where parent =
client_ip_addr % num_parents.
I don't understand what that means. Does it effectively pin a parent
to a particular Client IP?
> Round_robin=strict is just a strict round roubin over the array of
parents.
>
> Thanks
> John Rushford
> jrushf...@apache.org
>
> On 11/2/16, 10:21 AM, "Miles Libbey" <mlib...@apache.org> wrote:
>
> Hey folks-
>
> I'd like to update the parent.config documentation to include the
> weightings feature -- there is an example that shows it, but no text
> that describes it. So, I have some questions :)
>
> - I assume that if someone includes a weight for each parent, the
> round robin=true turns into weighted round robin. I'd guess that ATS
> will sum the weighted values of all the parents, then send each parent
> (its value)/(sum of weights) of the traffic. True? In the example
> (p1.x.com:8080|1.0; p2.y.com:8080|2.0), would p1 get 1/3 of the
> traffic, and p2 would get the remaining 2/3rds?
>
> - In
https://docs.trafficserver.apache.org/en/latest/admin-guide/files/parent.config.en.html#examples
> , there is an example that has a weighting, even though the selection
> strategy is consistent hash. How does that work? Do the parents just
> get added to the ring that percentage more time? Like in the example,
> p1 gets added to the ring 1 time, and p2 gets added 2 times?
>
> - Does the weighting affect round_robin=strict and latched?
>
> - Is there a max value to the weighting? Anything special about the
> decimal (for instance, is there a limit to the precision?)
>
> Also, what is the difference between round_robin=true and
round_robin=strict?
>
> thanks!
>
> miles
>
>
>
>
