Hi, I'm aware of at least 2 ways: 1. create 6 node cluster, restore snapshot to it from original cluster; and reduce this second cluster to 3 nodes. in this case, you should be careful in picking nodes to be decommissioned to avoid additional rebalance of cluster and changing tokens.
2. prepare the original cluster for multi-DC configuration; add second DC with 3 nodes. in this case, you can also switch to vnodes in 2nd, new DC, which is good idea hope this helps. 2015-06-22 6:25 GMT+03:00 John Wong <gokoproj...@gmail.com>: > Hi. > > Supposed I have a 6-node cluster running and I want to build a 3-node > cluster based on that 6-node cluster. What is the recommended way to > quickly build such cluster? Each node is about 120Gb and we have RF=3. We > are on Cassandra 1.2.19 and we are not using vnode. > > My initial research shows it can either be done with sstableloader or > restore using snapshot and fix the token range. > > In the case of sstableloader, given it is streaming, and we are restoring > from a live server, this seems to be a slow process if we throttle the > traffic. Even if I take this route, do I just pick 3 node out of the 6 > nodes in any random order? > > In the case of restoring from snapshots I have restored a 6-node replica > with just copying snapshot files (along with schema files), run nodetool > refresh, and should be able to complete in a few hours. But now with > smaller replica, do I again just pick snapshots from any 3 nodes? What and > why do I need to fix token range (from what I read)? > > Any feedback is appreciated. > > Thanks. > > John > -- ---- with best regards, Vitalii Skakun
