D-UN-DY-23 EMC Dell Unity Deploy 2023 Exam Free Practice Exam Questions (2025 Updated)

A Host Group is a logical grouping of hosts that share the same access permissions to storage objects, such as LUNs, VMFS Datastores, or NFS Filesystems. By configuring a Host Group, an administrator can simplify the management of multiple hosts and ensure consistent access to the storage resources. Some of the benefits of using a Host Group are:

Provides multiple hosts access to the same VMFS Datastores: 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. A VMFS Datastore can be shared by multiple hosts that are part of a VMware cluster. By adding these hosts to a Host Group and assigning the VMFS Datastore to the Host Group, the administrator can ensure that all the hosts have the same access permissions and can access the virtual machines on the Datastore.

Provides multiple hosts access to the same LUNs: A LUN is a block-based storage object that is presented to a host as a SCSI device. A LUN can be shared by multiple hosts that have the same operating system and use a cluster-aware file system. By adding these hosts to a Host Group and assigning the LUN to the Host Group, the administrator can ensure that all the hosts have the same access permissions and can access the data on the LUN.

The total cache availability for caching the flash drives on a Dell Unity XT 480 system with one pool of flash drives, 192 GB of RAM, and 1.2 TB of FAST Cache is 3.58 TB. This is calculated by adding the system memory (RAM), the FAST Cache, and the pool cache. The system memory is 192 GB, which is equivalent to 0.18 TB. The FAST Cache is 1.2 TB, which is a dedicated cache for the flash drives. The pool cache is 2.2 TB, which is a portion of the flash drives that is reserved for caching the pool data. Therefore, the total cache availability is 0.18 + 1.2 + 2.2 = 3.58 TB.

A feature that can be configured for a Dell Unity XT file system NFS share is the Host Access Level. This feature allows the user to specify the access permissions for each host or host group that is allowed to access the NFS share. The access permissions can be set to Read/Write, Read Only, or No Access. The Host Access Level feature can be used to control the security and performance of the NFS share. Access-Based Enumeration, Protocol Encryption, and Distributed File System are features that can be configured for a Dell Unity XT file system SMB share, not NFS share.

If the time difference between the current system (UTC) time and the NTP server time is too large (approximately 17 minutes), the user cannot configure an NTP server during initial configuration. The user will need to adjust the time while in “Set time manually” mode before changing to “Enable NTP synchronization”. This is to avoid potential issues with data replication, snapshots, and audit logs that rely on accurate time stamps. References: Dell EMC Unity: How to change System Time from ‘Set time manually’ option to NTP2, page 1.

 Mixing FC and iSCSI protocols for the same host and array is not supported by Dell EMC Unity. This can cause issues with multipathing, failover, and performance. The best practice is to use one protocol per host and array pair. If the host needs to access both FC and iSCSI LUNs from different arrays, then separate vSwitches and port groups should be used for each protocol. References: Dell EMC Unity: Best Practices Guide1, page 19.

The maximum number of replicated NAS servers supported for the Dell Unity XT 380 series in an asynchronous replication is 126. This is the same as the maximum number of NAS servers supported for the Dell Unity XT 380 series in general. Asynchronous replication is a method of replicating data between two Dell Unity systems with a configurable recovery point objective (RPO). It allows the source system to continue normal operations without waiting for the destination system to acknowledge the completion of the replication.

Data Reduction is a feature that reduces the amount of physical storage space required to store user data on a LUN. Data Reduction is enabled at the LUN level and applies to all the data in the LUN, including snapshots and thin clones. Data Reduction consists of two components: compression and deduplication. Compression reduces the size of data blocks by removing redundant information, while deduplication eliminates duplicate blocks across the LUN. When Data Reduction is enabled on a LUN, all writes to the LUN will go through the Data Reduction logic before being written to the storage pool. If the LUN is part of a consistency group, Data Reduction will be enabled on all the LUNs in the consistency group, and all writes to any LUN in the group will go through the Data Reduction logic. This ensures that the data in the consistency group is consistent and protected by the same Data Reduction settings. References:

Dell EMC Unity: Data Reduction Overview

Dell EMC Unity: Data Reduction Configuration and Best Practices

The maximum number of drives on a traditional RAID group depends on the RAID type and the drive type. For RAID 5 and RAID 6, the maximum number of drives is 16 for all drive types. For RAID 1/0, the maximum number of drives is 32 for SAS and NL-SAS drives, and 16 for SSD drives. References: Dell EMC Unity: Best Practices Guide2, page 17.

To meet the requirements, the replication connection mode must be set to Both, which allows both synchronous and asynchronous replication sessions to be configured on the same connection. This way, block resources can use synchronous replication, which ensures zero data loss, and file resources can use asynchronous replication, which allows some data difference on the destination. Setting Unisphere resource filtering to All is not necessary, as it only affects the display of resources in the Unisphere GUI. Setting an RPO of 0 on the synchronous replication sessions is redundant, as synchronous replication always has an RPO of 0. Configuring the replication interfaces on the 4-port mezzanine card is not relevant, as it only affects the performance and availability of the replication network.

To grant access of a Dell Unity XT provisioned NFS datastore to an ESXi host, the permission level required for the host depends on the NFS protocol and authentication method used by the NAS server. For NFSv4 with Kerberos NFS owner authentication, the ESXi host must have the Read/write, enable Root permission level. This allows the ESXi host to read and write data to the datastore, as well as perform administrative tasks such as creating and deleting virtual machines. The Read/write permission level alone is not sufficient, as it does not allow the ESXi host to perform root-level operations on the datastore. The Read-only permission level only allows the ESXi host to read data from the datastore, but not write or modify it. References: Dell EMC Unity: Configuring hosts to access NFS1, page 9.