[jboss-jira] [JBoss JIRA] (JGRP-1595) STABLE2

[Bela Ban (JIRA)]

     [ https://issues.jboss.org/browse/JGRP-1595?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Bela Ban updated JGRP-1595:
---------------------------

    Description: 
While JGRP-1570 only changes the default for desired_avg_gossip and max_bytes (not scaling them with the cluster size), this issue is about a new stable protocol, STABLE2, which works well in large clusters without generating too much traffic.
It works as follows:

* A dedicated member (the coord) periodically multicast a STABLE message
* Everyone replies with a (unicast) STABLE message and when the coord has received STABLE replies from everyone, it multicasts a STABILITY message
* This would only require a multicast from the coord to everyone, establishing TCP connections from the coord to everyone (usually already exists because of the VIEW-CHANGE multicast), but everyone would reuse the same TCP connection to send the reply

Another solution could be that every member sends its STABLE message to the current coordinator (triggered by time or size), and when the coordinator has received STABLE messages from all members, it multicasts  a STABILITY message

  was:
The time computed for the sending of STABLE is desired_avg_gossip * cluster-size *2. While this is OK for small clusters, it may be too big for large clusters.
On the other hand, if every member simply multicasts a STABLE message every (say) 30 seconds on average, then the number of messages sent grows with increasing cluster size.
Investigate a way to set a lower and upper limit for the making and delivery of *STABILITY* messages, e.g. the goal is to receive 1 stability message every 60s.

Besides increased traffic, however, this requires everyone to have a TCP connection to everybody else in the cluster in case of a TCP transport.

A better solution might be to have only a dedicated member (the coord) periodically multicast a STABLE message. Everyone replies with a (unicast) STABLE message and when the coord has received STABLE replies from everyone, it multicasts a STABILITY message. This would only require a multicast from the coord to everyone, establishing TCP connections from the coord to everyone (usually already exists because of the VIEW-CHANGE multicast), but everyone would reuse the same TCP connection to send the reply.


    
> STABLE2
> -------
>
>                 Key: JGRP-1595
>                 URL: https://issues.jboss.org/browse/JGRP-1595
>             Project: JGroups
>          Issue Type: Feature Request
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>             Fix For: 3.3
>
>
> While JGRP-1570 only changes the default for desired_avg_gossip and max_bytes (not scaling them with the cluster size), this issue is about a new stable protocol, STABLE2, which works well in large clusters without generating too much traffic.
> It works as follows:
> * A dedicated member (the coord) periodically multicast a STABLE message
> * Everyone replies with a (unicast) STABLE message and when the coord has received STABLE replies from everyone, it multicasts a STABILITY message
> * This would only require a multicast from the coord to everyone, establishing TCP connections from the coord to everyone (usually already exists because of the VIEW-CHANGE multicast), but everyone would reuse the same TCP connection to send the reply
> Another solution could be that every member sends its STABLE message to the current coordinator (triggered by time or size), and when the coordinator has received STABLE messages from all members, it multicasts  a STABILITY message

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