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https://issues.apache.org/jira/browse/CASSANDRA-2434?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13094818#comment-13094818
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Nick Bailey commented on CASSANDRA-2434:
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Seems to me like the option to stream from the closest replica might just add
more confusion without really gaining anything. The node that is leaving the
replica set will never be in another datacenter. It could be on a different
rack, but if you are following best practices and alternating racks then it is
likely either on the same rack or there is only one copy on that rack and the
best case possible is streaming from another rack anyway.
> node bootstrapping can violate consistency
> ------------------------------------------
>
> Key: CASSANDRA-2434
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2434
> Project: Cassandra
> Issue Type: Bug
> Reporter: Peter Schuller
> Assignee: paul cannon
> Fix For: 1.1
>
> Attachments: 2434.patch.txt
>
>
> My reading (a while ago) of the code indicates that there is no logic
> involved during bootstrapping that avoids consistency level violations. If I
> recall correctly it just grabs neighbors that are currently up.
> There are at least two issues I have with this behavior:
> * If I have a cluster where I have applications relying on QUORUM with RF=3,
> and bootstrapping complete based on only one node, I have just violated the
> supposedly guaranteed consistency semantics of the cluster.
> * Nodes can flap up and down at any time, so even if a human takes care to
> look at which nodes are up and things about it carefully before
> bootstrapping, there's no guarantee.
> A complication is that not only does it depend on use-case where this is an
> issue (if all you ever do you do at CL.ONE, it's fine); even in a cluster
> which is otherwise used for QUORUM operations you may wish to accept
> less-than-quorum nodes during bootstrap in various emergency situations.
> A potential easy fix is to have bootstrap take an argument which is the
> number of hosts to bootstrap from, or to assume QUORUM if none is given.
> (A related concern is bootstrapping across data centers. You may *want* to
> bootstrap to a local node and then do a repair to avoid sending loads of data
> across DC:s while still achieving consistency. Or even if you don't care
> about the consistency issues, I don't think there is currently a way to
> bootstrap from local nodes only.)
> Thoughts?
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