EMC DEE-1111 Dumps

The -precopy option in the relink command can be used when you want to start copying data to the target devices immediately after the link operation. This can be useful in situations where additional volumes have been added, increasing the link to full copy time. By using -precopy, you ensure that the data starts copying immediately, preventing potential issues.

If an administrator implemented SYMACLs on a PowerMax using host-based Access IDs and is no longer able to run SYMCLI commands against the volumes belonging to a host, one possible reason could be that the SYMAPI options file was manually modified with the wrong host ID. The SYMAPI options file contains configuration settings for Solutions Enabler, including host IDs for access control. If this file is incorrectly modified, it could prevent the administrator from running SYMCLI commands against certain volumes34. References: Dell EMC PowerMax and VMAX All Flash: Embedded Management, Role Based Access Control on PowerMax – Storage Intelligence

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

 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

 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.

Fast Write is a Dell EMC technology that improves Fibre Channel (FC) replication between sites in a SRDF/S configuration. When a write I/O is issued by the host to the R1 device, SRDF with Fast Write acknowledges the write to the host as soon as the data is stored in the R1’s cache and transmitted to the R2’s cache. This results in reduced latency and improved performance for FC replication between sites.

For an SRDF/Metro personality swap, the SRDF/Metro devices must be Read/Write (RW) on the link. This ensures that data can be read from and written to the devices during the swap operation.

References: SRDF/Metro overview | Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices, Understanding bias | Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices

The symaudit -list command is used to display audit records for SYMCLI commands. The exhibit shows the output of the symauth -list command, which displays the user groups and access types defined for SYMCLI commands. The output shows that there are two user groups: AdminGrp and EmcMgmtGrp. The AdminGrp group has ADMINRD access type, which means that users in this group can run any SYMCLI command with read-only access. The EmcMgmtGrp group has BASECONTROL access type, which means that users in this group can run only a subset of SYMCLI commands with read/write access. However, the output also shows that there are two exceptions for specific users: Beth and Frank. Beth has ADMINRD access type for all commands, which overrides her membership in EmcMgmtGrp group. Frank has BASECONTROL access type for all commands, which overrides his membership in AdminGrp group. Therefore, the only user who has access to run the symaudit -list command based on the symauth output shown in the exhibit is Beth, since she has ADMINRD access type for all commands2

When the RDF-ECA timer expires, all RDF links will be in a ‘Suspend’ state. This is because the RDF-ECA timer is used to control how long SRDF waits for an acknowledgement from the remote array before it suspends the link. If an acknowledgement is not received within this time, SRDF assumes that there is a problem with the link or remote array and suspends the link to prevent data loss or corruption.

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

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

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 PowerMax, each RAID group is divided into 64 logical blocks known as TDATs (Thin Device Addressable Tracks). Each TDAT is configured to hold data at a given data reduction level, from 1:1 uncompressed data all the way to 16:11. References: Data Protection Schemes | Dell PowerMax: Reliability, Availability, and Serviceability | Dell Technologies Info Hub

The correct sequence of steps to configure and bring up an SRDF/Star environment is as follows:

• Verify SRDF/Star control host connectivity and array settings. This step involves checking the network connectivity between the control host and the three arrays involved in the SRDF/Star configuration, as well as verifying the array settings such as RDF mode, RDF consistency, and RDF emulation. The control host is the host that runs the Solutions Enabler SYMCLI commands to manage the SRDF/Star configuration.The three arrays are the primary array, the secondary array, and the tertiary array.1
• Enable SRDF/Star configuration. This step involves enabling the SRDF/Star feature on the primary array using the symstar enable command. This command also creates a STAR control device group on the primary array, which contains a single device that acts as a control point for the SRDF/Star configuration.The STAR control device group must have a unique name and number across all arrays.1
• Add BCV devices to the SRDF/Star configuration. This step involves adding Business Continuance Volume (BCV) devices to the STAR control device group on the primary array using the symstar add bcv command. BCV devices are local copies of data that can be used for backup, restore, or testing purposes. BCV devices are required for SRDF/Star configurations to enable fast recovery in case of a disaster.The number of BCV devices must match the number of R1 devices in the SRDF/Star configuration.1
• Create an SRDF/Star composite group and options file. This step involves creating an SRDF/Star composite group on the control host using the symstar create command. An SRDF/Star composite group is a logical grouping of devices that span across three arrays and have different SRDF roles: R11, R21, and R22. An R11 device is an R1 device that is paired with another R1 device in a different SRDF group. An R21 device is an R2 device that is paired with another R1 device in a different SRDF group. An R22 device is an R2 device that is paired with another R2 device in a different SRDF group.The symstar create command also creates an options file that contains various parameters for the SRDF/Star configuration, such as RDF mode, RDF consistency, RDF emulation, and bias setting.1
• Perform the symstar setup operation and create composite groups on target sites. This step involves performing the symstar setup operation on the control host using the symstar setup command. This command establishes the SRDF/Star configuration by creating RDF pairs between devices in different arrays, creating RDF groups on each array, creating composite groups on each array, and synchronizing data across all devices.The symstar setup command also creates composite groups on the secondary and tertiary arrays using the same name and number as the composite group on the primary array.1

References:

• Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide

During a Non-Disruptive Migration (NDM), issuing the ReadyTgt SYMCLI command to the migrating Storage Group completes the migration by removing the migrated application resources from the source array2. This command is typically issued after all data has been synchronized from the source to the target array and application I/O has been switched to thetarget array2. References: NDM overview | Dell EMC PowerMax and VMAX: Non-Disruptive Migration Best Practices and Operational Guide | Dell Technologies Info Hub