Doris securely deletes BE nodes

The DECOMMISSION statement is as follows:

ALTER SYSTEM DECOMMISSION BACKEND "be_host:be_heartbeat_service_port";

DECOMMISSION command description:

1. This command is used to safely delete BE nodes. After the command is issued, Doris will try to migrate the data on the BE to other BE nodes, and when all the data is migrated, Doris will automatically delete the node.
2. This command is an asynchronous operation. After execution, you can  SHOW PROC '/backends'; see that the status of the BE node  SystemDecommissioned is true. Indicates that the node is going offline.
3. The command does not necessarily execute successfully . For example, if the remaining BE storage space is not enough to accommodate the data on the offline BE, or the number of remaining machines does not meet the minimum number of copies, the command cannot be completed, and BE will always be in the true state  SystemDecommissioned .
4. The progress of DECOMMISSION can  SHOW PROC '/backends'; be viewed through TabletNum in , if it is in progress, TabletNum will keep decreasing.
5. This operation can be
   CANCEL DECOMMISSION BACKEND "be_host:be_heartbeat_service_port";
   canceled by the :command. After cancellation, the data on the BE will maintain the current remaining data volume. Subsequent Doris will re-balance the load

ALTER SYSTEM DECOMMISSION BACKEND "bigData08:9050";

SHOW PROC '/backends'\G;

The number of TabletNum is constantly decreasing. After the number is reduced, execute SHOW PROC '/backends'\G; to see that there are no more 248 nodes

Stop doris-be on node 248

/opt/doris/doris-be/bin/stop_be.sh

ALTER SYSTEM DECOMMISSION BACKEND "bigData05:9050";