DEE-1111 Sample Questions Answers

A noisy neighbor issue occurs when one or more applications consume more resources than expected, causing performance degradation for other applications. This can affect the SL compliance of a storage group, as the service level defines the expected response time and performance for the applications in that group. If a noisy neighbor consumes too much cache, bandwidth, or CPU cycles, it can cause the SL compliance to drop below the target level. Therefore, answer A is correct.

B, C, and D are incorrect because they are not likely to cause SL compliance impact for a storage group. Queue depth full event (B) is a host-side issue that occurs when the host queue depth is too low or the host I/O rate is too high, causing the host to stop sending I/O requests to the array. Host queue depth setting © is also a host-side parameter that determines how many I/O requests can be queued by the host. Performance thresholds (D) are user-defined values that trigger alerts when certain metrics exceed or fall below the specified levels. None of these factors affect the SL compliance of a storage group on the array.

In a Concurrent SRDF/Star environment where the production data on R11 devices are replicated to two R2 devices in two remote arrays, SRDF/S links must be configured between Site 3 and Site 2. This is because in a Concurrent SRDF/Star configuration, there are two target sites and one source site. If there’s a failure, the source site can switch to either of the target sites based on the business continuity plan1. References: Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide, SRDF Star software uses and best practices - Dell

 If utilization increases by 10% for both systems A and B, where system A has a current utilization of 10% and system B has a current utilization of 70%, the response times for systems A and B would not necessarily increase linearly with utilization. The exact impact on response times would depend on various factors including workload characteristics, system configuration, and resource contention among others34. However, without specific details on these factors, it’s not possible to provide an accurate prediction for the new response times. References: PowerMax and VMAX All Flash: Storage Resource Pool (SRP) Effective Used Capacity threshold alert, Service levels and eNAS | Dell EMC PowerMax and VMAX All Flash: eNAS Best Practices

The symstar halt command is used to write disable devices and synchronize SRDF data to remote sites in an SRDF/Star configuration. This command ensures that all sites have a consistent copy of data before switching the workload site from one site to another. Therefore, the symstar halt command should be used before the workload switch in case of a disaster at the workload site of an SRDF/Star configuration1

 If an administrator has added custom SSL certificates and each time a client connection is made, default certificates are used, then ‘restart storsrvd’ must be completed. This is because changes to SSL certificates often require a restart of the service that uses them in order for the new certificates to be correctly loaded and used for future client connections1.

 In a SRDF/Metro deployment in a clustered host configuration, when the RDF link state is partitioned and the R1 side has full read/write capability to the application, the R2 device also has full read/write capability to the application. With SRDF/Metro, both R1 and R2 devices may then appear as a single virtual device across the two SRDF paired arrays for host presentation. With both the R1 and R2 devices being accessible, the host or hosts (in the case of a cluster) can read and write to both R1 and R2 devices with SRDF/Metro ensuring that each copy remains current, consistent, and addressing any write conflicts which may occur between the paired SRDF devices23. References: Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices, Deploying Dell EMC SRDF/Metro Smart DR with Microsoft SQL Server for Physical and Virtual Environments

 When maintenance tasks at the R1 data center require the array to be offline, a Swap operation should be executed on the Metro RDF pairs. This operation allows for a planned outage without affecting application I/O by swapping the roles of R1 and R2 devices. 

The SYMACL unique ID for a host system can be obtained in two ways: derived from a host-based passphrase or randomly generated by the Solutions Enabler lockbox file. The host-based passphrase is a string that the user can specify to generate a unique ID for the host. The passphrase can be entered interactively using the symacl -unique -passphrase command, or stored in a file and passed as an argument using the symacl -unique -passphrase -file command. The Solutions Enabler lockbox file is a secure file that stores encryption keys and other sensitive information. The lockbox file can also generate a random unique ID for the host using the symacl -unique command. The lockbox file must be created and initialized before using this method.

References:

• symacl -unique : Unable to obtain unique ID for host - Dell
• EMC – Symmetrix Access Control – symacl | SANSPIRE
• How to identify hostname and host ID for license generation

https://infohub.delltechnologies.com/l/dell-emc-powermax-and-vmax-non-disruptive-migration-best-practices-and-operational-guide-1/ndm-overview

Before configuring Access Control, the security administrator must define the User Access ID for the Admin User. This is a necessary step to ensure that the administrator has the necessary permissions to perform this operation.

PowerMax & VMAX All-Flash Storage Technical Documentation, Dell EMC PowerMax and VMAX All Flash: Embedded Management

The data characteristics represent an Online Transaction Processing (OLTP) workload profile. OLTP workloads typically consist of a high percentage of small, random I/O operations2. In this case, 80% of the I/O is generated with 8 KB random small blocks, which is characteristic of OLTP workloads2. References: Use DISKSPD to test workload storage performance - Azure Stack HCI | Microsoft Learn

Data Domain is the only external storage that can be connected to PowerMax using DX emulation. DX emulation is a specialized back-end DA emulation that handles SAN attached disks. DX directors are configured on existing PowerMax front-end Fibre Channel ports and are required to be implemented in pairs for high availability. DX emulation is used to support ProtectPoint technology, which integrates primary storage with Data Domain protection storage to accelerate backup and recovery. Therefore, answer A is correct1.

B, C, and D are incorrect because they are not external storage that can be connected to PowerMax using DX emulation. Unity (B), PowerStore ©, and Compellent (D) are primary storage arrays that do not support ProtectPoint technology or DX emulation.

In an SRDF/Metro configuration, if the host is cross-connected and the R2 device becomes Not Ready, the host continues to have read/write access to the R1 device12. This is because SRDF/Metro is designed to provide high availability and continuous data access. If one device becomes inaccessible, the host can still access the other device12. References: SRDF/Metro | SAP Landscape Consolidation with Dell Components, Understanding bias | Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices