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From aaron morton <aa...@thelastpickle.com>
Subject Re: Expanding cluster to include a new DR datacenter
Date Mon, 27 Aug 2012 08:35:04 GMT
I did a quick test on a clean 1.1.4 and it worked 

Can you check the logs for errors ? Can you see your schema change in there ?

Also what is the output from show schema; in the cli ? 

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 25/08/2012, at 6:53 PM, Bryce Godfrey <Bryce.Godfrey@azaleos.com> wrote:

> Yes
>  
> [default@unknown] describe cluster;
> Cluster Information:
>    Snitch: org.apache.cassandra.locator.PropertyFileSnitch
>    Partitioner: org.apache.cassandra.dht.RandomPartitioner
>    Schema versions:
>         9511e292-f1b6-3f78-b781-4c90aeb6b0f6: [10.20.8.4, 10.20.8.5, 10.20.8.1, 10.20.8.2,
10.20.8.3]
>  
> From: Mohit Anchlia [mailto:mohitanchlia@gmail.com] 
> Sent: Friday, August 24, 2012 1:55 PM
> To: user@cassandra.apache.org
> Subject: Re: Expanding cluster to include a new DR datacenter
>  
> 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] 
> 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
> 


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