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From Rakesh Rajan <rakes...@gmail.com>
Subject Re: High loads only on one node in the cluster
Date Fri, 01 Nov 2013 17:54:14 GMT
Tyler,

Thanks for the explanation. The objective is not to have a perfectly
balanced US-East and SG DC clusters. SG DC cluster is just a backup cluster
and hence has lesser nodes than US-East cluster. What we are trying to
figure out is the imbalance between the 6 nodes within US-East itself. I'll
try to correct the 6 nodes with US-East to proper racks and check.

In addition, as I mentioned earlier, do you see any issues with the dynamic
snitch attribute score? I see that node has high score, but what value of
dynamic_snitch_badness_threshold should I set so that other replicas can
get the traffic? ( that node has >50% higher score than all other nodes )


On Fri, Nov 1, 2013 at 10:04 PM, Tyler Hobbs <tyler@datastax.com> wrote:

>
> On Fri, Nov 1, 2013 at 5:07 AM, Rakesh Rajan <rakeshxp@gmail.com> wrote:
>
>>
>> 1) By alternating racks, do you mean to alternate racks between all nodes
>> in a single DC v/s multiple DCs? AWS EastCoast has 4 AZs
>> and Singapore has 2 AZs. So is the final solution something like this:
>> ip11 - East Coast - m1.xlarge / us-east-1b         - Token: 0
>> ip21 - Singapore  - m1.xlarge / ap-southeast-1a - Token: 1001
>> ip12 - East Coast - m1.xlarge / us-east-*1c*         -
>> Token: 28356863910078205288614550619314017621
>> ip13 - East Coast - m1.xlarge / us-east-*1d*         -
>> Token: 56713727820156410577229101238628035241
>> ip22 - Singapore  - m1.xlarge / ap-southeast-1b -
>> Token: 56713727820156410577229101238628036241
>> ip14 - East Coast - m1.xlarge / us-east-*1a*         -
>> Token: 85070591730234615865843651857942052863
>> ip15 - East Coast - m1.xlarge / us-east-*1b*         -
>> Token: 113427455640312821154458202477256070484
>> ip23 - Singapore  - m1.xlarge / ap-southeast-*1a* -
>> Token: 113427455640312821154458202477256071484
>> ip16 - East Coast - m1.xlarge / us-east-*1c*         -
>> Token: 141784319550391026443072753096570088105
>>
>> Is this what you had suggested?
>>
>
> That would be more balanced than your current setup, but it would still be
> unbalanced, especially the ap-southeast DC.  To have a perfectly balanced
> cluster with multiple racks, you need to a) have the same number of nodes
> on each rack, and b) alternate racks within each DC.  Your new layout would
> meet requirement (b), but not (a).  This is why I suggest using the same
> rack for all nodes.
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>
>

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