The recovery key is effectively the "Master Key" for that specific datastore chunk. If lost, data is cryptographically garbage.
In the context of VMware environments, a VMFS Recovery Key typically refers to the license key required to activate professional data recovery software designed for VMware’s Virtual Machine File System (VMFS). While VMware itself uses "keys" for ESXi licensing, the term "recovery key" is most often associated with third-party tools used to salvage data from corrupted volumes, deleted virtual disks (VMDKs), or failed RAID arrays. Understanding VMFS Recovery Software VMFS is a high-performance cluster file system used by VMware ESXi. Because it is proprietary, standard Windows or Linux recovery tools cannot natively read its structure. Specialized software, such as vmfs recovery key
This is the core reason you are reading this guide. You have a datastore that is locked, and the host cannot mount it automatically because the TPM is cleared or the host was reinstalled. The recovery key is effectively the "Master Key"