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Date: Mon, 6 Feb 2012 05:13:59 +0000 (UTC)
From: "Peter Schuller (Created) (JIRA)" <jira@apache.org>
To: commits@cassandra.apache.org
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Subject: [jira] [Created] (CASSANDRA-3858) expose "propagation delay" metric
 in JMX
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expose "propagation delay" metric in JMX
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                 Key: CASSANDRA-3858
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-3858
             Project: Cassandra
          Issue Type: Improvement
          Components: Core
            Reporter: Peter Schuller
            Priority: Minor


My idea is to augment the gossip protocol to contain timestamps. We wouldn't use the timestamps for anything "important", but we could use them to allow each node to expose a number which is the number of milliseconds (or seconds) "old" information is about nodes that are "the oldest" and also alive.

When nodes go down you'd see spikes, but for most cases where nodes live, this information should give you a pretty good idea of how fast gossip information is propagating through the cluster, assuming you keep your clocks in synch.

It should be a good thing to have graphed, and to have alerts on.


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