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

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]

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 DellUnityVSA 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.

References:

Dell EMC Unity: Introduction to the Platform

Dell EMC Unity: Deploying VMware vSphere with Dell EMC UnityVSA

Dell EMC Unity: Configuring Hosts to Access Block Storage

Dell EMC Unity: Replication Technologies

The purpose of a Proxy NAS server is to access snapshot replicas on the destination side of a replicated file resource. A Proxy NAS server is a temporary NAS server that is created on the destination system to mount a snapshot replica of a replicated file system. This allows the user to access the data on the snapshot replica for testing, recovery, or other purposes. A Proxy NAS server does not increase performance or security of production NAS servers, nor does it access snapshots for testing production NAS servers.

References: [Dell EMC Unity: Replication Technologies], [Dell EMC Unity: File System Configuration]

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

FAST VP (Fully Automated Storage Tiering for Virtual Pools) is a feature that automatically moves data within a storage pool based on the performance requirements and access patterns of the data. FAST VP data relocation runs in the background according to a user-defined schedule and rate. The schedule determines when the data relocation starts and ends, and the rate determines how much system resources are used for the data relocation. Users can set the Fast VP data relocation rate to High, Medium, Low, or None. High means that the data relocation has the highest priority and uses the most system resources, while None means that the data relocation is disabled. Fast VP data relocation does not run at all times, but only during the scheduled window. Fast VP optimizes data placement by moving 256 MB slices between disk tiers, not 1 GB slices. Users cannot enable or disable FAST VP at the LUN level, but only at the storage pool level.

References: [Dell EMC Unity: FAST Technology Overview], [Dell EMC Unity: Storage Pools and RAID Groups]

Two ways to create an asynchronous replication session for a NAS server are to use NAS server properties and to use the NAS server wizard. Both methods allow the user to select a source NAS server and a destination NAS server, and configure the replication settings, such as the RPO, the replication schedule, and the replication mode. Creating a replication connection or a replication interface are not ways to create an asynchronous replication session for a NAS server, but rather prerequisites for enabling replication between two Dell Unity systems.

References: [Dell EMC Unity: Replication Technologies], [Dell EMC Unity: NAS Capabilities]

Host configuration is the process of defining the host properties and access permissions for a host that connects to the Dell Unity XT system. For NFS clients, the host configuration requires two prerequisites:

Network Address: The network address is the IP address or the subnet mask of the NFS client that identifies the host on the network. The network address is used to register the host on the Dell Unity XT system and to grant access to the NFS filesystems.

Hostname: The hostname is the name of the NFS client that is resolved by the DNS server or the local hosts file. The hostname is used to display the host information on the Unisphere UI and to enable host monitoring and alerting.

References:

Dell EMC Unity: Host Configuration

Dell EMC Unity: File System Configuration and Management

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.

References: [Dell EMC Unity: Unisphere Overview], [Dell EMC Unity: Service Tasks]

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.