[jira] [Comment Edited] (CASSANDRA-12104) Handle coalesce efforts for inter-dc traffic discretely from intra-dc traffic

["Ariel Weisberg (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-12104?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15362749#comment-15362749 ] 

Ariel Weisberg edited comment on CASSANDRA-12104 at 7/5/16 5:00 PM:
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How were you able to tell they had a positive effect on inter-dc traffic if you were experiencing a negative impact to intra-dc traffic? What is the metric you are using?


was (Author: aweisberg):
How were you able to tell they had a positive on inter-dc traffic if you were experiencing a negative impact to intra-dc traffic? What is the metric you are using?

> Handle coalesce efforts for inter-dc traffic discretely from intra-dc traffic
> -----------------------------------------------------------------------------
>
>                 Key: CASSANDRA-12104
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-12104
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Thom Valley
>            Priority: Minor
>
> In relationship to CASSANDRA-8692, we have discovered that pushing coalescing windows to the point where they have a positive impact on inter-dc traffic overhead appears to have causes delays in intra-dc traffic (namely, quorum requests between nodes).  Having the same coalescing strategy apply to all messages (especially intra-dc request/response messages) seems like a bad idea.
> This was in a 5 DC environment with from 30 to 130 ms of latency between the DCs.  Local network was entirely unrestricted 10G ethernet.
> Being able to apply different coalescing rules to those two classifications of traffic would allow much more effective tuning of the coalescing strategies, save inter-dc bandwidth while not having any impact on intra-dc message handling.



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