DEE-1111 Questions and Answers

The correct sequence of actions that take place on a Write Miss is as follows:

• Host sends requests to FE director and no cache slots are found.This happens when the cache is full or the desired cache slot is locked by another request1.
• FE finds available slot by polling.This involves the FE director scanning the cache for an available slot or waiting for a slot to be freed by the BE director2.
• FE sends data from host to mirrored cache locations.This involves the FE director writing the data from the host to two mirrored locations in the cache, one on each engine2.
• FE responds to host to acknowledge successful write.This involves the FE director sending a signal to the host that the write operation is completed, even though the data is not yet written to disk2.
• BE destages data as a high-priority task to make slots available.This involves the BE director flushing some of the existing write pending data from the cache to the disk, in order to free up some cache slots for new write requests2.
• BE destages new data to disk at a later time.This involves the BE director writing the new data from the cache to the disk, according to the destaging algorithm and priority2.

During a Non-Disruptive Migration (NDM), when the migration is committed, the host access to the source array is removed by deleting the masking view. The masking view is a logical grouping of host initiators, storage ports, and a storage group (which contains volumes). Deleting the masking view removes the host’s access to the volumes on the source array12. References: Dell EMC PowerMax and VMAX: Non-Disruptive Migration Best Practices and Operational Guide, VMAX/PowerMax Non-Disruptive Migration (NDM) for the IBMi host platform | Dell US Support Knowledge Base Article

The steps in sequence as part of key management for a drive failure on a PowerMax array are as follows:

• Spare drive invoked against failed drive. This step involves the system automatically selecting a spare drive and starting the sparing operation to rebuild the data from the failed drive.The spare drive is encrypted with a temporary key that is stored in the embedded key manager.1
• 1st entry in audit log.This step involves the system logging the sparing operation and the temporary key generation in the audit log, which records all key management activities and events.1
• Sparing operation is completed. This step involves the system completing the data rebuild and marking the spare drive as a permanent replacement for the failed drive.The spare drive becomes part of the RAID group and inherits the same properties as the failed drive.1
• Key is deleted from the repository when failed drive is removed. This step involves the system deleting the Data Encryption Key (DEK) of the failed drive from the embedded key manager when the failed drive is physically removed from the array.The DEK is a unique 256-bit AES-XTS key that is used to encrypt and decrypt data on each drive.1
• 2nd entry in audit log.This step involves the system logging the DEK deletion and the failed drive removal in the audit log.1
• Key is generated for the replacement drive when installed. This step involves the system generating a new DEK for the replacement drive when it is installed in the array.The new DEK is stored in the embedded key manager and used to encrypt and decrypt data on the replacement drive.1

References:

• Dell EMC PowerMax and VMAX All Flash: Data at Rest Encryption

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

In a Concurrent SRDF/Star configuration failure, the first step to recover is to switch to the 1st Target Site. 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

The user has been assigned the RemoteRep role only. The RemoteRep role allows users to create, manage, and delete SRDF device pairs, as well as view array information, masking objects, device information, and RBAC rules2. However, it does not allow users to create and delete SRDF groups, which requires the StorageAdmin role. Therefore, answer C is correct.

A, B, and D are incorrect because they do not match the user’s profile. SecurityAdmin (A) role allows users to manage security settings such as authentication methods, certificates, RBAC rules, and audit logs2. Auditor (B) role allows users to view array information and audit logs only2. LocalRep (D) role allows users to create, manage, and delete TimeFinder SnapVX sessions from a source device2. None of these roles allow users to create and delete SRDF device pairs.

In an SRDF/Star configuration, all SRDF/Star device pairs must be of the same geometry and size. This is because SRDF/Star uses concurrent SRDF to maintain synchronous and asynchronous SRDF sessions between three arrays. The devices in these sessions must have identical geometry to ensure data consistency56. References: Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide, SRDF/Metro overview | Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices

 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.

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

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. A Service Level is a predefined set of performance attributes that can be applied to a storage group to ensure consistent and predictable performance. A Service Level specifies a target response time, an upper response time limit, and a lower response time limit for the storage group. If the application owner wants to improve theperformance of their application, they can adjust the Service Level to a higher level of service, which will provide lower response times and higher priority for the storage group. Unisphere for PowerMax provides five predefined Service Levels: Diamond, Platinum, Gold, Silver, and Bronze, as well as an Optimized option that automatically adjusts the Service Level based on workload characteristics. The application owner can choose a higher Service Level from these options or create a custom Service Level with their own performance parameters.

References:

• Dell EMC PowerMax: Service Levels for PowerMaxOS
• Dell Unisphere for PowerMax 10.0.0 Product 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