D-UN-DY-23 Sample Questions Answers

The Unity XT 680 system supports four types of I/O modules: 12 Gb/s SAS back-end, 4-Port 16 Gb Fibre Channel, 4-Port 25 Gbps Ethernet, and 4-Port 10 Gbps Ethernet. The 12 Gb/s SAS back-end module provides connectivity to the disk drives and expansion enclosures, while the other three types of modules provide network connectivity to the hosts and clients. The Unity XT 680 system has six I/O module slots, three for each SP. The 12 Gb/s SAS back-end module must be installed in slot 0 of each SP, and the other modules can be installed in slots 1 and 2 of each SP. Therefore, the correct answer is D. 12 Gb/s SAS back-end. References:

• Dell EMC Unity XT: Hardware Information Guide
• Dell EMC Unity XT: Installation Guide

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

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.

References: [Dell EMC Unity: File System Configuration], [Dell EMC Unity: SMB Share Configuration]

When deploying Dell UnityVSA OVA, the recommended disk format is Thick Provision Eager Zeroed, which allocates and zeroes out all the space for the virtual disks at the time of creation. This ensures better performance and avoids potential issues with thin provisioning on the underlying storage. Thin Provision and Thick Provision Lazy Zeroed are not recommended, as they may cause performance degradation and unexpected out-of-space errors.

References: [Dell EMC UnityVSA Installation Guide], [Dell EMC UnityVSA Best Practices Guide]

The correct sequence of steps to provision storage for SMB NAS clients is:

• Group hard drives into storage pools. This allows you to create a pool of storage resources that can be allocated to different types of storage objects, such as NAS servers, file systems, and LUNs.You can create different pools based on the performance and capacity requirements of your applications1
• Create a NAS server for an existing pool. A NAS server is a logical entity that provides file-level access to clients using SMB, NFS, or FTP/SFTP protocols. You need to create a NAS server before you can create file systems and shares.You can specify the pool, network settings, domain membership, and other properties for the NAS server2
• Create file systems and file system shares based on the supported NAS protocol. A file system is a logical container that stores files and folders on a NAS server. A file system share is a logical representation of a file system that can be accessed by clients using a specific protocol. For SMB NAS clients, you need to create SMB file system shares that support the SMB protocol.You can configure the share name, permissions, access policies, and other settings for the SMB share3
• Map the shared file system to the client. This allows the client to access the files and folders on the SMB share using a drive letter or a UNC path.You can use the Windows Explorer or the net use command to map the shared file system to the client4

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

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.

References:

• Dell EMC Unity: Host Configuration
• Dell EMC Unity: VMware ESXi Hosts and Clusters