Directory growing after restarting of one node

[immanens]

Hi,
I've 2 nodes version 1.5.2 under debian stable (8.7) .
I just migration storage of esnode by doing a (stupid) copy after shuting down the node. there is no indexing operations during the copy. the copy took 1 day.

when I start the node this morning, I saw intense network traffics between 2nodes and the node whom I migrated the storage is making grow up esnode folder. it is becoming much more bigger then the other's.
should I let it finish off what they are doing? or, just remove all files and restart the node, which makes a full resync between 2 nodes and it take 1 more day?

thanks for yours helps
regards
curl 'localhost:9200/_cluster/health?level=indices&pretty'

{
"cluster_name" : "my-secret-cluster1",
"status" : "yellow",
"timed_out" : false,
"number_of_nodes" : 2,
"number_of_data_nodes" : 2,
"active_primary_shards" : 5,
"active_shards" : 5,
"relocating_shards" : 0,
"initializing_shards" : 2,
"unassigned_shards" : 3,
"number_of_pending_tasks" : 0,
"indices" : {
"secret-prod" : {
"status" : "yellow",
"number_of_shards" : 5,
"number_of_replicas" : 1,
"active_primary_shards" : 5,
"active_shards" : 5,
"relocating_shards" : 0,
"initializing_shards" : 2,
"unassigned_shards" : 3
}
}
}

[warkolm (Mark Walkom)]

You should 1) upgrade ASAP, and 2) just leave it. It's syncing and given you are on such an old version, it'll take a while.

[immanens]

ok. I choose debian packaged version. If I SHOULD put a newer version, it's not a problem for me.
the problem is the folder is growing up quickly, I wonder why it's doing that, and I hope It will not take as big as the original size, I don't have double of 624Go on my iscsi LUN !