Yes, you need to have a VMware ESX host to perform instantly recovery. You can also perform read and write operation on the Virtual Machine. You can perform VMware Storage migration to migrate the Instantly Recovery VM back to production storage.
Please refer the release note of Veritax Backup Exec 15 Feature Pack 5:
https://www.veritas.com/support/en_US/article.000114987
Instant Recovery (IR) for Virtual Machines (VMWare and Hyper-V)
Backup Exec lets you recover a virtual machine instantly without waiting to transfer the virtual machine’s data from a backup set. Backup Exec starts the instantly recovered virtual machine directly from the backup set and users can access it on the ESX/Hyper-V host immediately. The startup time depends on the network speed and storage speed and not on the size of the virtual machine. You can use an instantly recovered virtual machine for all operations that you can do on a virtual machine. For more information about this feature, see "About instant recovery of a VMware virtual machine" and 'About instant recovery of a Hyper-V virtual machine' in the Backup Exec 15 Administrator's Guide.
What’s new in Backup Exec 15 Feature Pack 5?
https://vox.veritas.com/t5/Backup-Recovery-Community-Blog/What-s-new-in-Backup-Exec-15-Feature-Pack-5/ba-p/814705
What are the requirements for Instant Recovery?
“Host-based” VMware or Hyper-V backup sets
- Backups using the Agent for VMware and Hyper-V (VM selected from the virtualization host)
- Backups must have File-Folder GRT enabled
Backup sets must be stored on a disk device
- Deduplication, OST, disk cartridge, USB, cloud, VTL and tape storage are NOT supported for Instant Recovery
- Backup sets duplicated from a non-supported source to a disk device are supported for Instant Recovery
How this feature works?
- A virtualized copy of the backup(s) is made available to the virtualization host as an NFS (VMware) or SMB (Hyper-V) share.
- The virtualization host creates a VM from the virtualized copy of the backup.
- To handle the writes to the instantly recovered VM, a snapshot is taken for the newly created VM.
- Reads of existing data happen from the virtualized copy on the Backup Exec server.
- The backup set and related dependencies are marked as retained to prevent DLM grooming.
- Optional : Use vMotion or Live Migration to make a new permanent copy of the recovered VM.