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From Redmumba <redmu...@gmail.com>
Subject Re: adding more nodes into the cluster
Date Fri, 01 Aug 2014 16:32:02 GMT
The Cassandra wiki is notoriously out of date.  The Datastax documentation
is generally more correct on most things.


On Fri, Aug 1, 2014 at 9:27 AM, Donald Smith <
Donald.Smith@audiencescience.com> wrote:

>  According to datastax’s documentation at
> http://www.datastax.com/documentation/cassandra/2.0/cassandra/operations/ops_add_dc_to_cluster_t.html
>
>    “By default, this setting [auto_bootstrap] is true and not listed in
> the cassandra.yaml file.”
>
>
>
> But http://wiki.apache.org/cassandra/StorageConfiguration  says:
>
>    “Default is: 'false', so that new clusters don't bootstrap immediately.
> You should turn this on when you start adding new nodes to a cluster that
> already has data on it.”
>
>
>
> So which is correct?
>
>  Also, the two pages disagree on the instructions on how to add new nodes
> to an existing cluster.  The first page says to set auto_boostrap to ‘
> *false’* when adding a new data center to a cluster. “Setting this
> parameter to false prevents the new nodes from attempting to get all the
> data from the other nodes in the data center. When you run nodetool
> rebuild
> <http://www.datastax.com/documentation/cassandra/2.0/cassandra/tools/toolsRebuild.html>
> in the last step, each node is properly mapped.”
>
>
>
> The second page suggests setting auto_boostrap to ‘*true’* when you add
> new nodes to an existing cluster: “You should turn this on when you start
> adding new nodes to a cluster that already has data on it.”  Perhaps that
> applies only to new nodes to an existing data center (not a new data center
> to an existing cluster).
>
>
>
> So, I’m not clear what I should do.   I want to add a data center to an
> existing cluster.   If I set auto_bootstrap to true in the new nodes of the
> new cluster, will it stream data from the other data centers?  Perhaps it
> will stream only NEW rows.   Perhaps the purpose of doing “nodetool
> rebuild” is to force streaming OLD data (like a repair).  It’s not clear.
> Maybe auto_bootstrap=true is equivalent to (auto_boostrap=false plus
> “nodetool rebuild”).
>
>
>
> Thoughts?
>
>  Don
>
> *Donald A. Smith* | Senior Software Engineer
> P: 425.201.3900 x 3866
> C: (206) 819-5965
> F: (646) 443-2333
> donalds@AudienceScience.com
>
>
> [image: AudienceScience]
>
>
>
>
>
> *From:* Robert Coli [mailto:rcoli@eventbrite.com]
> *Sent:* Wednesday, July 16, 2014 12:31 PM
> *To:* user@cassandra.apache.org
> *Subject:* Re: adding more nodes into the cluster
>
>
>
> On Wed, Jul 16, 2014 at 12:28 PM, Robert Coli <rcoli@eventbrite.com>
> wrote:
>
> It applies whenever one is bootstrapping a node. One is bootstrapping a
> node whenever one starts a node with auto_bootstrap set to "true" (the
> default) and with either one-or-more tokens in initial_token or num_tokens
> set.
>
>
>
> Ugh sorry :
>
>
>
> 1) starting a node
>
> 2) with auto_bootstrap:true (default)
>
> 3) initial_token or num_tokens populated
>
> 4) node has never successfully bootstrapped before, and has not therefore
> written the information of its successful bootstrap to the system keyspace
>
>
>
> If the node has bootstrapped before, it will not do so again unless
> replace_address is used.
>
>
>
> =Rob
>
>
>
>
>

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