Cassandra upgrade from 2.0.x to 2.1.x or 3.0.x
<p>I've searched for previous versions of this question, but none seem to fit my case. I have an existing Cassandra cluster running 2.0.x. I've been allocated new VMs, so I do NOT want to upgrade my existing Cassandra nodes - rather I want to migrate to a) new VMs and b) a more current version of Cassandra.</p>

<ol>
<li><p>I know for in-place upgrades, I would upgrade to the latest 2.0.x, then to the latest 2.1.x. AFAIK, there's no SSTable inconsistency here. If I go this route via addition of new nodes, I assume I would follow the datastax instructions for adding new nodes/decommissioning old nodes?</p></li>
<li><p>Given the above, is it possible to move from 2.0.x to 3.0.x? I know the SSTable format is different; however, if I'm adding new nodes (rather than re-using SSTables on disk), does this matter? </p></li>
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<p>It seems to me that #2 has to work - otherwise, it implies that any upgrade requiring SSTable upgrades would require all nodes to be taken offline simultaneously; otherwise, there would be mixed 2.x.x and 3.0.x versions running in the same cluster at some point.</p>

<p>Am I completely wrong? Does anyone have any experience doing this? </p>