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From Igor <i...@4friends.od.ua>
Subject Re: How to add new DC to cluster when GossipingPropertyFileSnitch is used
Date Fri, 17 May 2013 08:04:10 GMT
I see no reason to restart all nodes. You can continue to use seed from 
first DC - seed used for loading ring configuration(locations, token 
ranges, etc), not data.

On 05/17/2013 10:34 AM, Sergey Naumov wrote:
> If I understand you correctly, GossipingPropertyFileSnitch is useful 
> for manipulations with nodes within a single DC, but to add a new DC 
> without having to restart every node in all DCs (because seeds are 
> specified in cassandra.yaml and I need to restart a node after 
> addition of a new seed from newly created DC), I anyway have to use 
> cassandra-topology.properties and edit it on every node of a cluster.
>
> By the way, it it necessary to specify seeds if I use 
> PropertyFileSnitch and there is info in cassandra-topology.properties 
> about all nodes of a cluster?
>

Yes, it is. Cassandra need seed(s), because topology properties have no 
info about token ranges.

>
> 2013/5/17 aaron morton <aaron@thelastpickle.com 
> <mailto:aaron@thelastpickle.com>>
>
>     You should configure the seeds as recommended regardless of the
>     snitch used.
>
>     You need to update the yaml file to start using the
>     GossipingPropertyFileSnitch but after that it reads the
>     cassandra-rackdc.properties file to get information about the
>     node. It reads uses the information in gossip to get information
>     about the other nodes in the cluster.
>
>     If there is no info in gossip about a remote node, because say it
>     has not been upgraded, it will fall back to using
>     cassandra-topology.properties.
>
>     Hope that helps.
>
>     -----------------
>     Aaron Morton
>     Freelance Cassandra Consultant
>     New Zealand
>
>     @aaronmorton
>     http://www.thelastpickle.com
>
>     On 15/05/2013, at 8:10 PM, Sergey Naumov <sknaumov@gmail.com
>     <mailto:sknaumov@gmail.com>> wrote:
>
>     > As far as I understand, GossipingPropertyFileSnitch supposed to
>     provide more flexibility in nodes addition/removal. But what about
>     addition of a DC? In datastax documentation
>     (http://www.datastax.com/docs/1.2/operations/add_replace_nodes#add-dc)
>     it is said that cassandra-topology.properties could be updated
>     without restart for PropertyFileSnitch. But here
>     (http://www.datastax.com/docs/1.0/initialize/cluster_init_multi_dc) it
>     it said, that "you MUST include at least one node from EACH data
>     center. It is a best practice to have at more than one seed node
>     per data center and the seed list should be the same for each
>     node". At the first glance it seems that PropertyFileSnitch will
>     get necessary info from cassandra-topology.properties, but for
>     GossipingPropertyFileSnitch modification of cassandra.yaml and
>     restart of all nodes in all DCs will be required. Could somebody
>     clarify this topic?
>     >
>     > Thanks in advance,
>     > Sergey Naumov.
>
>


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