You cannot use the identical token ranges. You have to capture membership information somewhere for each datacenter, and use that token information when briging up the replacement DC.
You can find details on this process here: http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_snapshot_restore_new_cluster.html That process is straight forward, but it can go south pretty quickly if you miss a step. It's a really good idea to set asside some time to try this out in a staging/test system and build a runbook for the process targeting your specific environment. On Fri, Aug 28, 2015 at 1:12 PM, sai krishnam raju potturi < pskraj...@gmail.com> wrote: > > hi; > We have cassandra cluster with Vnodes spanning across 3 data centers. > We take backup of the snapshots from one datacenter. > In a doomsday scenario, we want to restore a downed datacenter, with > snapshots from another datacenter. We have same number of nodes in each > datacenter. > > 1 : We know it requires copying the snapshots and their corresponding > token ranges to the nodes in new datacenter, and running nodetool refresh. > > 2 : The question is, we will now have 2 datacenters, with the same exact > token ranges. Will that cause any problem. > > DC1 : Node-1 : token1......token10 > Node-2 : token11 .....token20 > Node-3 : token21 ..... token30 > Node-4 : token31 ..... token40 > > DC2 : Node-1 : token1.....token10 > Node-2 : token11....token20 > Node-3 : token21....token30 > Node-4 : token31....token40 > > > thanks > Sai > > > > -- ----------------- Nate McCall Austin, TX @zznate Co-Founder & Sr. Technical Consultant Apache Cassandra Consulting http://www.thelastpickle.com
