Hello Subhankar,
as stated in the "dynamic tiering"-administration guide:
"You can also install a second extended storage host, known as the standby, to provide failover functionality for high availability."
So you cannot install a second esserver as a worker.
Please refer to the following guides:
Dynamic Tiering Administration
Dynamic Tiering Installation
In the Installation Guide you may want to pay special attention to chapter 8.1 or 8.2 depending on the installation tools you are using.
BR, Bojan