Hot-warm 'move index' does not delete index data from original node

Hello,

I'm experimenting with introducing a 'warm' data node as explained here: https://www.elastic.co/blog/hot-warm-architecture

I've allocated my indices to my 'hot' node and have attempted to move a single index to my 'warm' node, which appears to have been successful. I moved an index called analytics-pageview-2016-08-30 - here's the pertinent output from /cat/_shards:

analytics-pageview-2016-09-20 1 p STARTED     967053 297.9mb 10.196.3.254 Ocean        
analytics-pageview-2016-09-20 1 r UNASSIGNED                                           
analytics-pageview-2016-09-20 0 p STARTED     966107 298.1mb 10.196.3.254 Ocean        
analytics-pageview-2016-09-20 0 r UNASSIGNED                                           
analytics-pageview-2016-08-30 1 p STARTED     841559 256.9mb 10.1.0.61    Lady Octopus 
analytics-pageview-2016-08-30 1 r UNASSIGNED                                           
analytics-pageview-2016-08-30 0 p STARTED     842086 255.9mb 10.1.0.61    Lady Octopus 
analytics-pageview-2016-08-30 0 r UNASSIGNED                                           
analytics-pageview-2016-08-31 1 p STARTED     920134 279.2mb 10.196.3.254 Ocean        
analytics-pageview-2016-08-31 1 r UNASSIGNED                                           
analytics-pageview-2016-08-31 0 p STARTED     919752 284.1mb 10.196.3.254 Ocean        
analytics-pageview-2016-08-31 0 r UNASSIGNED                                  

However on my 'hot' node, I can still see that index's data:

$ du -sh /var/lib/elasticsearch/elasticsearch/nodes/0/indices/analytics-pageview-2016-08-30
514M	/var/lib/elasticsearch/elasticsearch/nodes/0/indices/analytics-pageview-2016-08-30

Will this eventually be cleaned up by elasticsearch following some criteria being satisfied?

I'd greatly appreciate any advice you could offer.

yes, the criteria is that there are enough shard copies in the cluster. You specified that shards of this index must have 1 replica. In your current cluster, only the primary is allocated. As long as no replica is allocated, the cluster will keep the extra copy of the data around.

Ah - that makes sense. Thanks for taking the time to answer.