Explanation
A characteristic of Host Groups is that block storage resources added to a host group are accessible to all the member hosts. A Host Group is a logical grouping of hosts that share the same access permissions and settings for block storage resources. By adding block storage resources to a host group, the user can simplify the management and allocation of storage for multiple hosts. Access to block storage resources does not need to be set before adding hosts to a host group, as the access permissions can be modified later. Hosts added to a host group can have mapped block storage resources, as long as they are not in conflict with the host group resources. Block storage resources attached to one of the member hosts are not accessible to the entire host group, unless they are also added to the host group.
References: [Dell EMC Unity: Host Configuration], [Dell EMC Unity: Block Storage Provisioning]

Explanation
VMware datastore is a logical container that holds virtual machine files and other data. There are three types of VMware datastore that can be defined by using UI or CLI interfaces from the Dell Unity XT platform:
vVol (Block): A vVol datastore is a block-based storage object that is formatted with the VMware Virtual Volumes (vVol) framework and used to store virtual machine files and metadata. A vVol datastore can be created by using the Unisphere UI or the UEMCLI interface on the Dell Unity XT system. A vVol datastore can provide granular control, policy-based management, and improved performance for virtual machines.
NFS (File): An NFS datastore is a file-based storage object that is formatted with the Network File System (NFS) protocol and used to store virtual machine files and other data. An NFS datastore can be created by using the Unisphere UI or the UEMCLI interface on the Dell Unity XT system. An NFS datastore can provide scalability, flexibility, and efficiency for virtual machines.
VMFS (Block): A VMFS datastore is a block-based storage object that is formatted with the VMware File System (VMFS) and used to store virtual machine files and other data. A VMFS datastore can be created by using the Unisphere UI or the UEMCLI interface on the Dell Unity XT system. A VMFS datastore can provide high performance, reliability, and compatibility for virtual machines.
References:
Dell EMC Unity: VMware ESXi Hosts and Clusters
Dell EMC Unity: Unisphere Overview
Dell EMC Unity: Unisphere CLI User Guide

Explanation
The snapshot option that is set automatically when a pool is configured is the Pool Automatic Deletion Policy.
This option determines how the system handles the deletion of snapshots when the pool reaches a certain threshold of capacity utilization. The user can choose between three policies: Never Delete, Delete Oldest, or Delete LowestPriority. The Total Pool Consumption and the Snapshot Pool Consumption are not snapshot options, but rather metrics that show the amount of pool space consumed by the pool data and the snapshots respectively.
References: [Dell EMC Unity: Storage Pools and RAID Groups], [Dell EMC Unity: Snapshots and Thin Clones]

Explanation
On a Dell Unity XT file system asynchronous replication session, four system Snapshots are required to support replication. Two system Snapshots are created on the source file system, and two system Snapshots are created on the destination file system. The source system Snapshots are used to track the changes that need to be replicated, and the destination system Snapshots are used to apply the changes and maintain a consistent point-in-time copy of the source data. The system Snapshots are automatically created and managed by the replication engine and are not visible to the user.
References: [Dell EMC Unity: Replication Technologies], [Dell EMC Unity: File System Configuration]

Explanation
To expand a dynamic pool, the number of drives added must be equal to or greater than the stripe width of the pool. The stripe width is the number of data drives plus the number of parity drives in a RAID group. In this case, the stripe width is 12 + 1 = 13. Therefore, the minimum number of drives needed for the pool expansion is 13. References: Dell EMC Unity: Dynamic Pools Technical White Paper1, page 8.