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From Mohit Anchlia <mohitanch...@gmail.com>
Subject Re: Expanding cluster to include a new DR datacenter
Date Fri, 24 Aug 2012 20:55:18 GMT
That's interesting can you do describe cluster?

On Fri, Aug 24, 2012 at 12:11 PM, Bryce Godfrey
<Bryce.Godfrey@azaleos.com>wrote:

>  So I’m at the point of updating the keyspaces from Simple to
> NetworkTopology and I’m not sure if the changes are being accepted using
> Cassandra-cli.****
>
> ** **
>
> I issue the change:****
>
> ** **
>
> [default@EBonding] update keyspace EBonding****
>
> ...     with placement_strategy =
> 'org.apache.cassandra.locator.NetworkTopologyStrategy'****
>
> ...     and strategy_options={Fisher:2};****
>
> 9511e292-f1b6-3f78-b781-4c90aeb6b0f6****
>
> Waiting for schema agreement...****
>
> ... schemas agree across the cluster****
>
> ** **
>
> Then I do a describe and it still shows the old strategy.  Is there
> something else that I need to do?  I’ve exited and restarted Cassandra-cli
> and it still shows the SimpleStrategy for that keyspace.  Other nodes show
> the same information.****
>
> ** **
>
> [default@EBonding] describe EBonding;****
>
> Keyspace: EBonding:****
>
>   Replication Strategy: org.apache.cassandra.locator.SimpleStrategy****
>
>   Durable Writes: true****
>
>     Options: [replication_factor:2]****
>
> ** **
>
> ** **
>
> *From:* Bryce Godfrey [mailto:Bryce.Godfrey@azaleos.com]
> *Sent:* Thursday, August 23, 2012 11:06 AM
> *To:* user@cassandra.apache.org
> *Subject:* RE: Expanding cluster to include a new DR datacenter****
>
> ** **
>
> Thanks for the information!  Answers my questions.****
>
> ** **
>
> *From:* Tyler Hobbs [mailto:tyler@datastax.com <tyler@datastax.com>]
> *Sent:* Wednesday, August 22, 2012 7:10 PM
> *To:* user@cassandra.apache.org
> *Subject:* Re: Expanding cluster to include a new DR datacenter****
>
> ** **
>
> If you didn't see this particular section, you may find it useful:
> http://www.datastax.com/docs/1.1/operations/cluster_management#adding-a-data-center-to-a-cluster
>
> Some comments inline:****
>
> On Wed, Aug 22, 2012 at 3:43 PM, Bryce Godfrey <Bryce.Godfrey@azaleos.com>
> wrote:****
>
>  We are in the process of building out a new DR system in another Data
> Center, and we want to mirror our Cassandra environment to that DR.  I have
> a couple questions on the best way to do this after reading the
> documentation on the Datastax website.  We didn’t initially plan for this
> to be a DR setup when first deployed a while ago due to budgeting, but now
> we need to.  So I’m just trying to nail down the order of doing this as
> well as any potential issues.****
>
>  ****
>
> For the nodes, we don’t plan on querying the servers in this DR until we
> fail over to this data center.   We are going to have 5 similar nodes in
> the DR, should I join them into the ring at token+1?****
>
>
> Join them at token+10 just to leave a little space.  Make sure you're
> using LOCAL_QUORUM for your queries instead of regular QUORUM.
>  ****
>
>   ****
>
> All keyspaces are set to the replication strategy of SimpleStrategy.  Can
> I change the replication strategy after joining the new nodes in the DR to
> NetworkTopologyStategy with the updated replication factor for each dr?***
> *
>
>
> Switch your keyspaces over to NetworkTopologyStrategy before adding the
> new nodes.  For the strategy options, just list the first dc until the
> second is up (e.g. {main_dc: 3}).
>  ****
>
>   ****
>
> Lastly, is changing snitch from default of SimpleSnitch to
> RackInferringSnitch going to cause any issues?  Since its in the
> Cassandra.yaml file I assume a rolling restart to pick up the value would
> be ok?****
>
>
> This is the first thing you'll want to do.  Unless your node IPs would
> naturally put all nodes in a DC in the same rack, I recommend using
> PropertyFileSnitch, explicitly using the same rack.  (I tend to prefer
> PFSnitch regardless; it's harder to accidentally mess up.)  A rolling
> restart is required to pick up the change.  Make sure to fill out
> cassandra-topology.properties first if using PFSnitch.
>  ****
>
>   ****
>
> This is all on Cassandra 1.1.4, Thanks for any help!****
>
>  ****
>
>  ****
>
>
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>****
>

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