Hi,
I am seeking for the best practice to restart a sharded SolrCloud that taking search traffic as well as realtime updates without downtime. When I deploy new customized Solr plugins,for example, it will require restarting the whole SolrCloud cluster. I am testing Solr 6.2.1 with 4 shards. And I find that when SolrCloud is taking updates, when I restart any Solr node (no matter whether it is a leader node or overseer or other normal replica), the restarted node would Reindex it's whole data from its leader. i.e., it will redownload the whole index data and then drop its old data. The only way I find to avoid such reindexing is to temporarily disable updates, such as invoke disableReplication in the leader node before restarting. Additionally, I didn't find a way to temporarily pause Solr replication to a single replica. Before sharding, we can do disablePoll to disable replication in a slave. But after sharding, disable replication from the leader node is the only way I found, which will pause not only the replication to the one node to restart, but also disable replication in all nodes in the same shard. The procedure becomes more complex if I want to restart a leader node: I need first manually trigger a leader node failover through rebalancing, then disable replication in the new leader node, then restart the old leader node, and at last reenable replication in the new leader node. As you can see, it seems to take many steps to restart SolrCloud node by node this way. I am not sure if this is the best procedure to restart the whole SolrCloud that is taking realtime update? Thanks! Sent from [Nylas N1](https://link.nylas.com/link/5tkvmhpozan5j5h3lhni487b /local-7bf8174b-7288/0?redirect=https%3A%2F%2Fnylas.com%2Fn1%3Fref%3Dn1&r=c29s ci11c2VyQGx1Y2VuZS5hcGFjaGUub3Jn), the extensible, open source mail client. 
