EMC D-UN-DY-23 Dell Unity Deploy 2023 Exam Exam Practice Test

The Dell UnityVSA is a software-defined storage solution that runs the Dell Unity operating environment on a VMware ESXi server. The Dell UnityVSA provides the same features and functions as the Dell Unity hardware platform, such as block and file storage, snapshots, thin clones, data reduction, replication, and encryption. Some of the features of the Dell UnityVSA are:

iSCSI Connectivity: The Dell UnityVSA supports iSCSI connectivity for block storage access. The iSCSI protocol enables hosts to communicate with the Dell UnityVSA over an IP network and access LUNs as SCSI devices. The Dell UnityVSA can support up to 64 iSCSI interfaces and up to 256 iSCSI sessions per interface.

Asynchronous Replication: The Dell UnityVSA supports asynchronous replication for block and file storage. Asynchronous replication is a feature that copies data from a source storage resource to a destination storage resource over a network at scheduled intervals. Asynchronous replication can be used for disaster recovery, data migration, or backup purposes. The Dell UnityVSA can support up to 256 replication sessions per system.

A LUN is a logical unit of storage that is presented to a host as a SCSI device. A LUN is composed of one or more RAID extents, which are the smallest units of storage that can be allocated to a LUN. A RAID extent is a slice of a RAID group that is used to store user data and parity information. The size of a RAID extent depends on the RAID type and the drive type of the RAID group. For example, a RAID 5 extent on a SAS drive is 128 MB, while a RAID 6 extent on a NL-SAS drive is 256 MB. The LUN is partitioned into slices that match the size of the RAID extents, and each slice is mapped to a RAID extent from a RAID group in the storage pool. The LUN slices are distributed across multiple RAID groups to improve performance and availability. References:

Dell EMC Unity: Storage Pools and RAID Groups

Dell EMC Unity: LUN Management

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 Lowest Priority. 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.

The firewall ports that are required to be open for a successful outbound connection when configuring integrated secure connect gateway are 443 and 8443. Integrated secure connect gateway is a feature that enables secure remote access to the Dell Unity system through the Unisphere Central web portal. It requires an outbound connection from the Dell Unity system to the Unisphere Central server over the internet. Port 443 is used for HTTPS communication and port 8443 is used for WebSocket communication.

The preferred FC Port for synchronous replication for a Dell Unity XT 380 system is Fibre Channel Port 4 of SPA and SPB. This port is dedicated for synchronous replication traffic and has the highest priority and bandwidth allocation. Synchronous replication is a method of replicating data between two Dell Unity systems with zero recovery point objective (RPO). It requires a low-latency and high-bandwidth network connection between the source and destination systems.

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.

When Advanced Deduplication is disabled on a LUN, the existing data that was deduplicated remains in its reduced state, and only new data written to the LUN is not deduplicated. To remove the Advanced Deduplication savings from the LUN, the administrator must perform a Local LUN Move operation, which copies the data from the source LUN to a destination LUN without deduplication. The destination LUN must have Advanced Deduplication disabled, and must be in the same storage pool as the source LUN. After the Local LUN Move is completed, the source LUN can be deleted and the destination LUN can be renamed as the original LUN. References: Dell Unity: Data Reduction2, page 9.

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.

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

Packet Reflect is a feature that enables the Dell Unity XT system to use the same interface for outbound communication that was used for inbound communication. This feature is useful when the Dell Unity XT system needs to initiate outbound traffic to an external service, such as DNS, NTP, LDAP, or SMTP. By using Packet Reflect, the Dell Unity XT system can avoid routing issues, firewall restrictions, or network address translation problems that may occur when using a different interface for outbound communication. When a NAS server starts outbound traffic to an external service, the Dell Unity XT system uses Packet Reflect to send the packets through the same interface that received the packets from the external service. Therefore, the correct answer is D. Uses Packet Reflect for outbound communication. References:

Dell EMC Unity: NAS Capabilities

Dell EMC Unity: Unisphere Overview

https://www.delltechnologies.com/asset/en-us/products/storage/industry-market/h15089-dell_emc_unity-snapshots_and_thin_clones.pdf

The service task that the administrator should perform to fix the issue with minimal impact is Restart Management Software. This service task restarts the management software on both storage processors without affecting the data services or the host I/O. This can resolve the communication issues between Unisphere and the storage system. Reinitialize, Enable SSH, and Reboot Storage Processor are service tasks that have more impact and risk than Restart Management Software.