[ceph-users] Best practice for expanding Ceph cluster

Dear Ceph folks, I am writing to ask for advice on best practice of expanding ceph cluster. We are running an 8-node Ceph cluster and RGW, and would like to add another 10 node, each of which have 10x 12TB HDD. The current 8-node has ca. 400TB user data. I am wondering whether to add 10 nodes at one shot and let the cluster to rebalance, or divide into 5 steps, each of which add 2 nodes and rebalance step by step? I do not know what would be the advantages or disadvantages with the one shot scheme vs 5 bataches of adding 2 nodes step-by-step. Any suggestions, experience sharing or advice are highly appreciated. thanks a lot in advance, Samuel huxiaoyu@horebdata.cn