EMC DEE-1111 - Expert - PowerMax and VMAX All Flash Solutions

The NDM Updates feature should be used to complete the migration and address the client’s concern. The NDM Updates feature is designed to help automate the process of moving applications across arrays requiring a short application downtime. It allows application migration from a VMAX (5876) array to a VMAX3 (5977), VMAX All Flash (5978), or PowerMax (5978) array1. It supports pre-sync data between arrays and then schedule downtime to do the cutover1. References: Dell EMC PowerMax and VMAX: Non-Disruptive Migration Best Practices and Operational Guide

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

An application owner is experiencing performance issues for their application. Unisphere for PowerMax is showing the storage group is compliant with the current Service Level. This means that the performance issue is not caused by the storage system, but by some other factor in the environment, such as network congestion, host configuration, or application workload. One possible way to address the performance issue is to redistribute the application to other front-end host ports on different directors. This can help balance the workload across multiple paths and avoid potential bottlenecks or contention on a single port or director. Unisphere for PowerMax provides a Performance Plan feature that can analyze the current configuration and suggest optimal port allocation for each storage group based on historical data and best practices.

References:

Understanding Performance Management

Dell EMC PowerMaxOS Performance Guide

The correct answer is D. When an SRDF/A MSC trip event occurs, the Receive Delta Set on the target arrays is checked for completeness. If the Receive Delta Set is incomplete on any of the target arrays, the session is marked as Cleanup required. This means that the data on the target arrays is not consistent and needs to be cleaned up before resuming SRDF/A replication. The symstar cleanup command can be used to discard the incomplete Receive Delta Set data and resume SRDF/A replication from the last consistent point1

he %Busy and Balance KPIs are the most important indicators of the BE performance on a PowerMax array. The %Busy metric shows the percentage of time that a BE director is busy processing I/O requests. A high %Busy value may indicate that the BE director is overloaded and cannot keep up with the demand. The Balance metric shows the difference in %Busy between the two BE directors in a pair. A high Balance value may indicate that the workload is not evenly distributed across the pair, which can lead to performance degradation. By monitoring these two KPIs, a storage administrator can identify and troubleshoot any potential issues with the BE performance.

References:

PowerMax Performance Troubleshooting with Unisphere - Run a real time trace at the system level

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

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

SRDF device used for Concurrent SRDF environments =R21

SRDF device used for SRDF/Star environments =R11

SRDF device used for Cascaded SRDF environments =R22

A dual personality SRDF device is a device that can act as both an R1 and an R2 device in different SRDF configurations. There are three types of dual personality SRDF devices: R21, R11, and R22.

An R21 device is an R2 device that is paired with another R1 device in a different SRDF group. This allows the R21 device to receive updates from the primary site and send updates to the secondary site. An R21 device is used for Concurrent SRDF environments, which provide simultaneous disaster recovery and data migration capabilities.For example, an R21 device can be used to migrate data from one array to another while maintaining a synchronous copy of the data on a third array.1

An R11 device is an R1 device that is paired with another R1 device in a different SRDF group. This allows the R11 device to receive updates from the primary site and send updates to the tertiary site. An R11 device is used for SRDF/Star environments, which provide three-site disaster recovery capabilities with a single hop between any two sites.For example, an R11 device can be used to create a synchronous copy of the data on a secondary site and an asynchronous copy of the data on a tertiary site.2

An R22 device is an R2 device that is paired with another R2 device in a different SRDF group. This allows the R22 device to receive updates from the secondary site and send updates to the tertiary site. An R22 device is used for Cascaded SRDF environments, which provide three-site disaster recovery capabilities with two hops between the primary and tertiary sites.For example, an R22 device can be used to create an asynchronous copy of the data on a secondary site and another asynchronous copy of the data on a tertiary site.3

References:

Dell EMC SRDF Introduction - Dell Technologies Partner Portal

Dell EMC PowerMax and VMAX All Flash: SRDF Product Guide

Dell EMC PowerMaxOS Performance Guide

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