![](https://webcf.waybackmachine.org/web/20211031114759im_/https://habrastorage.org/getpro/habr/upload_files/5b9/184/189/5b9184189e940a7affceb90e613a8951.jpg)
Once upon a time our DBA team had a task. We had to move a ZooKeeper ensemble which we had been using for Clickhouse cluster. Everyone is used to moving an ensemble by moving its data files. It seems easy and obvious but our Clickhouse cluster had more than 400 TB replicated data. All replication information had been collected in ZooKeeper cluster from the very beginning. At the end of the day we couldn’t miss even a row of data. Then we looked for information on the internet. Unfortunately there was a good tutorial about 3.4.5 and didn’t fit our version 3.6.2. So we decided to use “the extending” for moving our ensemble.