D-VPX-OE-A-24 Questions and Answers

The VPLEX Mobility feature is designed to address several use cases, but two of the most common ones are:

Tech Refresh: This involves the migration of data from older storage arrays to newer ones without disrupting access to the data.VPLEX Mobility facilitates this process by allowing data to be moved seamlessly between different storage systems, which is essential during technology upgrades1.

Workload Rebalance: This use case involves the dynamic movement of workloads across different storage systems to balance performance and capacity needs.VPLEX Mobility enables administrators to shift data to the most appropriate storage resources as demands change, ensuring optimal performance and utilization1.

References:

VPLEX Mobility: The VPLEX Mobility feature is a key component of the VPLEX system, providing the ability to move data across different storage installations within the same data center, across a campus, or within a geographical region1.

Tech Refresh: The technology refresh use case is particularly important for organizations that need to update their storage infrastructure without causing downtime or affecting ongoing operations.VPLEX Mobility allows for such updates to happen in the background, with no impact on users or applications1.

Workload Rebalance: Workload rebalance is crucial for maintaining performance levels across storage systems, especially in environments where workloads can be unpredictable or where there are periodic spikes in demand.VPLEX Mobility’s ability to move data dynamically helps in managing these scenarios effectively1.

For more detailed information on VPLEX Mobility and its use cases, you can refer to the official Dell documentation on VPLEX Overview and General Best Practices1.

Questions no:Q34

Verified Answer:D.ds dd create

Step by Step Comprehensive Detailed Explanation with References:

To create a distributed virtual volume from specified storage volumes in Dell VPLEX, the command used is ds dd create. This command stands for “distributed storage distributed device create” and is part of the VPLEX CLI (Command Line Interface) commands that manage distributed devices across clusters in a VPLEX Metro environment.

Command Usage: The ds dd create command is used to create a distributed device, which is a virtual volume that spans across two VPLEX clusters, providing high availability and data mobility1.

Distributed Virtual Volume: A distributed virtual volume in VPLEX is a volume that is accessible from both clusters in a VPLEX Metro configuration.It allows for simultaneous read and write operations from both locations1.

Creating the Volume: The process involves specifying the storage volumes from each cluster that will be part of the distributed device.The command then creates a virtual volume that combines these storage volumes into a single distributed device1.

High Availability: The resulting distributed virtual volume can be used in scenarios that require high availability, such as active-active data center configurations.It ensures that data is accessible even if one of the clusters becomes unavailable1.

CLI Command Structure: The VPLEX CLI commands follow a structured format where the initial letters indicate the scope and type of operation.In this case, ds indicates distributed storage, and dd indicates a distributed device, which together specify the creation of a distributed virtual volume1.

By using the ds dd create command, administrators can effectively set up distributed virtual volumes in a VPLEX Metro environment, leveraging the system’s capabilities for data availability and mobility.

To streamline the encapsulation process of LUNs across multiple servers to a VPLEX Metro cluster, the storage administrator can use the VIAS (VPLEX Integrated Array Services) Provisioning Wizard. This tool simplifies the process by automating many of the steps involved in encapsulating LUNs.

Here’s how the VIAS Provisioning Wizard can help:

Preparation: The administrator can prepare many of the encapsulation tasks ahead of time, such as host zoning to VPLEX FE ports, host registration of initiators in VPLEX, and LUN masking/zoning to the VPLEX BE Ports1.

Encapsulation Process: During the outage window, the administrator can use the VIAS Provisioning Wizard to encapsulate the LUNs under VPLEX control.Since the preparation steps like LUN masking and zoning to VPLEX BE have already been prepped, the cutover process becomes quicker1.

Storage View Container Creation: The VIAS Provisioning Wizard allows for the creation of a Storage View container in VPLEX, where only the VPLEX FE ports are included initially1.

EZ Provisioning Wizard: After claiming and encapsulating the LUNs, the administrator can create a 1:1 mapping of Storage volume to virtual volume with the EZ Provisioning Wizard, which is a quick process and helps preserve the data in its current state1.

Finalizing the Cutover: The newly encapsulated 1:1 virtual volumes are added to the previously created Storage View container, and the previously registered host initiators are added to the Storage View as well1.

By using the VIAS Provisioning Wizard, the administrator can efficiently manage the encapsulation of a large number of LUNs, reducing the complexity and duration of the outage window required for such a task.

In VPLEX, a valid target for device data migration is a device with no existing virtual volume. This is because the migration process involves moving data from a source device to a target device, and having an existing virtual volume on the target device could lead to data conflicts or loss.

Migration Process: The migration process in VPLEX is designed to move data from one storage device to another.This is typically done to upgrade storage, balance loads, or for other maintenance reasons1.

Target Device Requirements: The target device for migration should be a clean slate with no existing virtual volumes.This ensures that the data from the source device can be migrated without any issues1.

Device with Existing Virtual Volume: If a device already has a virtual volume, it is not a suitable target for migration because the existing data could be overwritten or corrupted during the migration process1.

Extent and Distributed Device: While extents and distributed devices are components within the VPLEX architecture, they are not the end targets for device data migration.The migration target needs to be a device that can be mapped to a virtual volume after the migration is complete1.

Migration Commands: VPLEX provides specific CLI commands to perform device data migration, ensuring that the process is controlled and that data integrity is maintained throughout the migration1.

By selecting a device with no existing virtual volume as the target for data migration, VPLEX administrators can ensure a smooth and error-free migration process, maintaining the integrity and availability of the data.

It is EMC best practice to ensure that each back-end LUN has a connection to all the A-directors and to all the B-directors in the VPLEX cluster to prevent data unavailability during a non-disruptive upgrade. Here’s why:

Non-Disruptive Upgrades: VPLEX allows for non-disruptive upgrades, meaning that system updates and maintenance can occur without impacting data availability or application performance1.

Director Connectivity: By connecting each back-end LUN to all A-directors and B-directors, VPLEX ensures that there are multiple paths for data access.If one director is being upgraded or is offline, the other directors can continue to provide access to the LUNs1.

High Availability: This connectivity model supports VPLEX’s high availability architecture, allowing for continuous operations even during maintenance activities1.

Redundancy: The practice of connecting LUNs to all directors provides redundancy, ensuring that there is no single point of failure that could lead to data unavailability1.

Best Practice: EMC recommends this approach as a best practice to maximize the uptime and resilience of the storage environment, which is critical for mission-critical applications that require constant data access1.

By following this best practice, organizations can leverage VPLEX’s capabilities to maintain data availability and ensure business continuity, even when system upgrades or director maintenance is required.

When setting up a VPLEX system that uses ESRS (EMC Secure Remote Services), it is essential to ensure that the correct ports are open to allow for various types of communication, including access to the VPLEX GUI. The port that needs to be opened on the firewall to allow access to the VPLEX GUI is port 443.

Port 443: This port is commonly used for HTTPS traffic, which is the protocol used for secure web communications.The VPLEX GUI is accessed over a web browser using HTTPS, hence the need for port 443 to be open1.

Firewall Configuration: The firewall administrator must configure the firewall to allow inbound and outbound traffic on port 443 to the VPLEX system’s IP address.This ensures that the technical support engineer and other users can access the VPLEX GUI through a secure connection1.

Troubleshooting Access Issues: If the technical support engineer cannot access the VPLEX GUI, one of the first steps in troubleshooting is to check the firewall settings to confirm that the necessary ports, including port 443, are open1.

ESRS Communication: While ports 25, 9010, and 5901 are important for ESRS communication and other services, they do not facilitate access to the VPLEX GUI.Port 25 is typically used for SMTP email services, port 9010 may be used for internal services, and port 5901 could be used for VNC or other remote access protocols1.

Secure Access: Opening port 443 not only allows access to the VPLEX GUI but also ensures that the communication is encrypted and secure, protecting sensitive data and system configurations1.

By opening port 443 on the firewall, the company ensures secure and reliable access to the VPLEX GUI for administration, monitoring, and troubleshooting purposes.

The correct order of steps to migrate from an old array to a new one without disruption using VPLEX is:

VPLEX discovers the new array and the admin creates migration target devices.

VPLEX admin initiates mobility job(s).

Once volumes on the new array are fully synchronized, the admin commits the migration.

VPLEX admin monitors progress of the migration; I/O to host continues.

Connect new storage array to VPLEX.

Discovery and Creation: The initial step involves VPLEX identifying the presence of a new storage array within its environment. Following this discovery, a system administrator is responsible for setting up migration target devices on this newly recognized array.

Initiation of Mobility Jobs: Subsequently, a system administrator must initiate mobility jobs through the VPLEX management interface, which facilitates data movement from the existing source storage to the target devices on the new array.

Synchronization and Commitment: After initiating mobility jobs, data synchronization between source and target arrays begins automatically. Once synchronization reaches completion, indicating that both arrays have identical data sets, an administrator must commit to finalizing this stage of migration.

Monitoring Migration Progress: Throughout this process, it’s crucial for an administrator to monitor ongoing operations ensuring that input/output operations continue uninterrupted for hosts accessing data during transition phases.

Connecting New Array: The final step involves integrating the newly populated storage array into production by connecting it with VPLEX systems thus completing migration.

Based on the information provided in the image, here is the explanation:

Storage Volume 1 (OB): This volume is listed with a capacity of 79.99 GB, health status OK, and status OK. Its use is indicated as ‘meta-data’, which typically means it is reserved for system or metadata use and not available for creating extents.

Storage Volume 2 (OA): This volume has a capacity of 6.00 GB, health status OK, and status OK. Its use is indicated as ‘unclaimed’, which suggests that it has not been allocated for any specific purpose yet and could potentially be used for creating an extent.

Storage Volume 3 (OD): This volume also has a capacity of 6.00 GB, health status OK, and status OK. However, its use is indicated as ‘claimed’, meaning it has already been allocated and is not available for creating new extents.

Storage Volume 4 (OC): The final volume has a capacity of 27.00 GB, health status OK, and status OK. Its use is indicated as ‘used’, which implies that it is currently in use and not available for creating new extents.

Based on the above analysis, the storage volume that is available to be used for the creation of an extent isStorage Volume 2 (OA). It is the only volume marked as ‘unclaimed’ and therefore available for new configurations such as creating extents.

The image provided appears to be a diagram or photograph of the back panel of a Dell VPLEX system. The back panel is divided into two sections, each presumably representing a director module. Each section has a set of ports highlighted and labeled with numbers 1, 2, 3, and 4. According to the question provided, which asks to identify the Director-A back-end ports from the options given (OA 1, OB 2, OC 4, OD 3), the verified answer is number 3. This can be inferred because typically in such systems, ‘A’ might refer to the first director or left side when looking at the back panel.

A VPLEX RAID-0 device is a configuration where data is striped across multiple storage volumes to improve performance. Here’s a detailed explanation:

RAID-0 Definition: RAID-0 is a disk array configuration that involves striping data across multiple disks without redundancy.This increases performance because I/O operations can be performed concurrently on all disks1.

Device Stripes Data: In the context of VPLEX, a device refers to a logical unit that is created from physical storage volumes.When a VPLEX device is configured as RAID-0, it stripes data across the underlying storage volumes1.

Top-Level Device: The term ‘top-level device’ refers to the logical device that is presented to hosts and applications.In VPLEX, this top-level device is the virtual volume that is created from one or more RAID-configured devices1.

Striping Beneath Top-Level Device: The striping occurs beneath the top-level device, meaning that it is handled within the VPLEX system and is transparent to the host.The host sees a single logical unit, while the VPLEX system manages the distribution of data across the physical volumes1.

Performance Considerations: RAID-0 devices provide better performance since data is retrieved from several storage volumes at the same time. However, RAID-0 devices do not include a mirror to provide data redundancy.They are used for non-critical data that requires high speed and low cost of implementation1.

By configuring a VPLEX device as RAID-0, administrators can leverage the performance benefits of striping for applications that require high throughput and do not need the redundancy provided by other RAID levels.

When a director fails and is removed from a VPLEX cluster, the global cache size decreases. This is because each director contributes to the total global cache available in the VPLEX cluster. Here’s the explanation:

Global Cache: The global cache in a VPLEX system is a shared resource that is used by all directors in the cluster to cache data for improved performance1.

Director Contribution: Each director within the VPLEX cluster has its own local cache, which collectively forms the global cache.When a director is operational, its cache is part of the global cache pool1.

Director Failure: If a director fails, its cache is no longer available to the cluster.As a result, the total size of the global cache is reduced by the amount that was contributed by the failed director1.

Removal from Cluster: When the failed director is physically removed from the cluster, its cache is permanently removed from the global cache pool, resulting in a decrease in the total global cache size1.

Impact on Performance: The reduction in global cache size may impact the performance of the VPLEX system, as there is less cache available for data storage and retrieval operations1.

System Architecture: VPLEX architecture allows for multiple director failures without loss of access to data down to a single director, but the global cache size will decrease with each director failure1.

By understanding the role of each director’s cache in contributing to the global cache, administrators can anticipate the effects of director failures on the overall performance of the VPLEX system.

In a VPLEX Metro environment without a Cluster Witness, the detach rules set for consistency groups (CGs) dictate the behavior during a WAN COM failure. Here’s what happens:

WAN COM Failure: A WAN COM failure means that the communication link between the two clusters in a VPLEX Metro has been lost.

Detach Rules: Detach rules are predefined actions that determine which cluster will continue to service I/O for a distributed virtual volume in the event of a communication failure.

CG1 and CG2: For App1, CG1 has a detach rule set with cluster-1 as the winner, meaning if there’s a WAN COM failure, cluster-1 will continue to service I/O for CG1, and I/O will be suspended at cluster-2. Conversely, for App2, CG2 has a detach rule set with cluster-2 as the winner, so cluster-2 will continue to service I/O for CG2, and I/O will be suspended at cluster-1.

Consequence of Extended WAN COM Failure: If the WAN COM failure is extended, the detach rules will be invoked, and each cluster will service the I/O for its respective application based on the set rules. This means that CG1 will be active on cluster-1 and suspended on cluster-2, and CG2 will be active on cluster-2 and suspended on cluster-1.

No Cluster Witness: Without a Cluster Witness, which usually arbitrates which cluster should remain active in case of a split-brain scenario, the detach rules are critical for maintaining data integrity and availability.

By setting appropriate detach rules, the company ensures that each application remains operational on one of the clusters, even during an extended WAN COM failure, thus maintaining availability according to the predetermined failover strategy.