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https://issues.apache.org/jira/browse/CASSANDRA-6127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13816044#comment-13816044
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Quentin Conner commented on CASSANDRA-6127:
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Tupshin, can you further quantify the CPU usage you observed, in terms of USER
CPU and KERNEL CPU?
Also, can you confirm the number of nodes and vnodes for those observations.
I've seen about 25% user cpu @ 256 nodes and 60% @ 512 nodes. Kernel cpu was
under 5% for both in my trials.
> vnodes don't scale to hundreds of nodes
> ---------------------------------------
>
> Key: CASSANDRA-6127
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6127
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: Any cluster that has vnodes and consists of hundreds of
> physical nodes.
> Reporter: Tupshin Harper
> Assignee: Jonathan Ellis
> Attachments: 2013-11-05_18-04-03_no_compression_cpu_time.png,
> 2013-11-05_18-09-38_compression_on_cpu_time.png, 6000vnodes.patch,
> AdjustableGossipPeriod.patch, delayEstimatorUntilStatisticallyValid.patch
>
>
> There are a lot of gossip-related issues related to very wide clusters that
> also have vnodes enabled. Let's use this ticket as a master in case there are
> sub-tickets.
> The most obvious symptom I've seen is with 1000 nodes in EC2 with m1.xlarge
> instances. Each node configured with 32 vnodes.
> Without vnodes, cluster spins up fine and is ready to handle requests within
> 30 minutes or less.
> With vnodes, nodes are reporting constant up/down flapping messages with no
> external load on the cluster. After a couple of hours, they were still
> flapping, had very high cpu load, and the cluster never looked like it was
> going to stabilize or be useful for traffic.
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