D-VPX-OE-A-24 Sample Questions & Answers

This is true. A key architectural requirement of a MetroPoint topology is the use of three sites. Site A and Site B host the active-active VPLEX Metro cluster, and Site C hosts the RecoverPoint cluster and the journal volumes. This ensures that the journal, which contains the history of writes, is isolated from a disaster affecting either of the primary production sites, enabling robust point-in-time recovery.

The cluster witness is a lightweight component located at a third site that is reachable by both VPLEX clusters. Its sole purpose is to provide a quorum device. If the link between the two clusters fails, each cluster will race to communicate with the witness. The cluster that successfully communicates with the witness is designated the 'winner' and continues I/O operations, while the other cluster suspends I/O. This prevents a 'split-brain' condition where both clusters might try to write to their respective copies of the data, leading to data corruption.

The primary architectural evolution from VS2 to VS6 is the move to newer hardware with more powerful multi-core CPUs and a faster, full-mesh back-end fabric (PCIe Gen3). This contrasts with the VS2's point-to-point back-end interconnect. The result is a substantial increase in performance, scalability, and I/O handling capacity, which is a common driver for upgrading.

When a leg of a RAID-1 device fails or is taken offline, it must be manually re-attached to initiate the rebuild process. The device attach-mirror command is used to specify the mirror (the dead leg) that needs to be brought back into the RAID-1 set. Once attached, VPLEX will automatically begin synchronizing the data from the healthy leg to the re-attached leg.

VPLEX Metro maintains cache coherency across sites. For a write I/O to be acknowledged, the data must be written to the local director's cache, transmitted across the WAN link, and successfully written to the remote director's cache. This ensures that both sites have a consistent, cached copy of the latest data before the host is notified of completion. The actual write to the back-end arrays (destaging) happens later as a background process.

RAID-C stands for concatenated device. It is specifically designed to allow for the non-disruptive expansion of a virtual volume by adding new extents to the end of the device. This is ideal for file systems that cannot be resized online, as the expansion happens at the block level beneath the file system. While other RAID types can be expanded, RAID-C is the simplest and most direct method for this specific use case.

Expanding a LUN at the storage level (in this case, VPLEX) does not automatically notify the host operating system of the size change. The host OS has already discovered the LUN with its original size. To recognize the new capacity, the host's SCSI bus must be rescanned. This action prompts the OS to re-query the LUN's attributes, including its size, making the new space available for use.

The registered initiators (host WWNs or iSCSI names) define which hosts are allowed to be part of the Storage View.

The VPLEX front-end ports define the physical paths through which the specified hosts can access the storage.

The virtual volumes are the logical storage units that will be presented to the hosts defined in the Storage View.

EMC Secure Remote Support (ESRS) is the service responsible for the 'call home' functionality. By configuring the VPLEX management server to communicate with an ESRS Gateway, the system can automatically send alerts, logs, and system reports to Dell Support upon detecting a hardware fault or critical event. This enables proactive monitoring and automated service request creation.

This statement is true. The fundamental building block of a VPLEX cluster is the engine. Each engine contains two redundant directors for high availability. Each of these directors is equipped with I/O modules that provide both front-end Fibre Channel ports for host connectivity and back-end Fibre Channel ports for connecting to the underlying storage arrays.