"Disk used" increases when rebalance is going on

I am using "Community Edition 6.6.0 build 7909 " in my project. I have three nodes in cluster. When one node from cluster gets failover(Node failed-over), i will click on “Add full recovery option”.
Then cb will ask to rebalance. Everything is fine till this point, but when click rebalance disk size increses significantly in all three nodes. From 60GB to 200 GB in each node, this will be same till rebalce gets completed.

I am not sure why this happens, also how can we minimize this much increase in data?
I am afraid it will affect my project anyhow.

Can someone guide me on same ? please!