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Posted to commits@cassandra.apache.org by "Tyler Hobbs (JIRA)" <ji...@apache.org> on 2015/11/17 23:25:11 UTC
[jira] [Commented] (CASSANDRA-6992) Bootstrap on vnodes clusters
can cause stampeding/storm behavior
[ https://issues.apache.org/jira/browse/CASSANDRA-6992?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15009705#comment-15009705 ]
Tyler Hobbs commented on CASSANDRA-6992:
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bq. We could also provide two tuning properties
I feel like adding config properties may just add unnecessary complexity to the config for something that would rarely need to be tuned, especially if our defaults are conservative. So, my personal preference is to pick conservative defaults and wait to see if anybody really needs to tune this.
> Bootstrap on vnodes clusters can cause stampeding/storm behavior
> ----------------------------------------------------------------
>
> Key: CASSANDRA-6992
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6992
> Project: Cassandra
> Issue Type: Improvement
> Components: Coordination, Streaming and Messaging
> Environment: Various vnodes-enabled clusters in EC2, m1.xlarge and hi1.4xlarge, ~3000-8000 tokens.
> Reporter: Rick Branson
> Assignee: Paulo Motta
> Priority: Minor
>
> Assuming this is an issue with vnodes clusters because SSTableReader#getPositionsForRanges is more expensive to compute with 256x the ranges, but could be wrong. On even well-provisioned hosts, this can cause a severe spike in network throughput & CPU utilization from a storm of flushes, which impacts long-tail times pretty badly. On weaker hosts (like m1.xlarge with ~500GB of data), it can result in minutes of churn while the node gets through StreamOut#createPendingFiles. This *might* be better in 2.0, but it's probably still reproducible because the bootstrapping node sends out all of it's streaming requests at once.
> I'm thinking that this could be staggered at the bootstrapping node to avoid the simultaneous spike across the whole cluster. Not sure on how to stagger it besides something very naive like one-at-a-time with a pause. Maybe this should also be throttled in StreamOut#createPendingFiles on the out-streaming host? Any thoughts?
> From the stack dump of one of our weaker nodes that was struggling for a few minutes just starting the StreamOut:
> "MiscStage:1" daemon prio=10 tid=0x000000000292f000 nid=0x688 runnable [0x00007f7b03df6000]
> java.lang.Thread.State: RUNNABLE
> at org.apache.cassandra.utils.ByteBufferUtil.readShortLength(ByteBufferUtil.java:361)
> at org.apache.cassandra.utils.ByteBufferUtil.readWithShortLength(ByteBufferUtil.java:371)
> at org.apache.cassandra.io.sstable.IndexHelper$IndexInfo.deserialize(IndexHelper.java:187)
> at org.apache.cassandra.db.RowIndexEntry$Serializer.deserialize(RowIndexEntry.java:125)
> at org.apache.cassandra.io.sstable.SSTableReader.getPosition(SSTableReader.java:889)
> at org.apache.cassandra.io.sstable.SSTableReader.getPosition(SSTableReader.java:790)
> at org.apache.cassandra.io.sstable.SSTableReader.getPositionsForRanges(SSTableReader.java:730)
> at org.apache.cassandra.streaming.StreamOut.createPendingFiles(StreamOut.java:172)
> at org.apache.cassandra.streaming.StreamOut.transferSSTables(StreamOut.java:157)
> at org.apache.cassandra.streaming.StreamOut.transferRanges(StreamOut.java:148)
> at org.apache.cassandra.streaming.StreamOut.transferRanges(StreamOut.java:116)
> at org.apache.cassandra.streaming.StreamRequestVerbHandler.doVerb(StreamRequestVerbHandler.java:44)
> at org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:56)
> at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
> at java.lang.Thread.run(Thread.java:662)
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