Re: How to change Replication Strategy and RF

[techpyaasa .]

Thanks a lot kurt Greaves

On Fri, Dec 30, 2016 at 5:58 AM, kurt Greaves  wrote:

>
> ​If you're already using the cluster in production and require no downtime
> you should perform a datacenter migration first to change the RF to 3.
> Rough process would be as follows:
>
>1. Change keyspace to NetworkTopologyStrategy with RF=1. You shouldn't
>increase RF here as you will receive read failures as not all nodes have
>the data they own. You would have to wait for a repair to complete to stop
>any read failures.
>2. Configure your clients to use a LOCAL_* consistency and
>DCAwareRoundRobinPolicy for load balancing (with the current DC configured)
>3. Add a new datacenter, configure it's replication to be 3.
>4. Rebuild the new datacenter by running nodetool rebuild  on
>each node in the new DC.
>5. Migrate your clients to use the new datacenter, by switching the
>contact points to nodes in the new DC and the load balancing policy DC to
>the new DC
>6. At this point you could increase the replication factor on the old
>DC to 3, and then run a repair. Once the repair successfully completes you
>should have 2 DCs that you can use. If you need the DCs in separate
>locations you could change this step to adding another DC in the desired
>other location and running rebuilds as per steps 2-4.
>
> - Kurt
>

Re: How to change Replication Strategy and RF

[kurt Greaves]

​If you're already using the cluster in production and require no downtime
you should perform a datacenter migration first to change the RF to 3.
Rough process would be as follows:

   1. Change keyspace to NetworkTopologyStrategy with RF=1. You shouldn't
   increase RF here as you will receive read failures as not all nodes have
   the data they own. You would have to wait for a repair to complete to stop
   any read failures.
   2. Configure your clients to use a LOCAL_* consistency and
   DCAwareRoundRobinPolicy for load balancing (with the current DC configured)
   3. Add a new datacenter, configure it's replication to be 3.
   4. Rebuild the new datacenter by running nodetool rebuild  on
   each node in the new DC.
   5. Migrate your clients to use the new datacenter, by switching the
   contact points to nodes in the new DC and the load balancing policy DC to
   the new DC
   6. At this point you could increase the replication factor on the old DC
   to 3, and then run a repair. Once the repair successfully completes you
   should have 2 DCs that you can use. If you need the DCs in separate
   locations you could change this step to adding another DC in the desired
   other location and running rebuilds as per steps 2-4.

- Kurt

How to change Replication Strategy and RF

[techpyaasa .]

Hi all,

We have mistakenly setup c*-2.0.17 cluster (with 1 DC , 3 racks , 2 nodes
in each rack with SimpleStrategy & *RF=1)*.
Now data on each node is nearly 1.4 GB+ .

Now we would like to change Replication Strategy to NetworkTopologyStrategy
and RF=3 and also add a new Data Center to this cluster.

Can someone please suggest *safest* way to do so.

Thanks in advance,
Techpyaasa