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When LUNs belonging to an ESXi cluster are encapsulated behind VPLEX, the information that must be shared with the ESXi administrator for them to re-discover the datastore and the RDM LUNs is the Virtual Volume VPD (Vital Product Data).

Virtual Volume VPD: The VPD for a virtual volume contains essential information about the volume, such as its identifier, which is used by the ESXi host to recognize and differentiate the volume1.

Re-Discovery Process: After encapsulation, the ESXi administrator will need to perform a rescan of the storage adapters on the ESXi hosts.During this rescan, the hosts use the VPD information to identify the newly encapsulated LUNs and re-discover the associated datastore and RDM LUNs1.

Datastore and RDM LUNs: Datastores are storage containers that hold virtual machine files, while RDM (Raw Device Mapping) LUNs allow a virtual machine to directly access a storage device.Both rely on unique identifiers to ensure correct access and operation within the ESXi environment1.

Sharing Information: The VPLEX administrator should provide the VPD information to the ESXi administrator, typically after the encapsulation process is complete and before the ESXi storage rescan is initiated1.

Ensuring Access: By sharing the correct VPD information, the ESXi administrator can ensure that the ESXi cluster correctly identifies and regains access to the encapsulated LUNs, maintaining the continuity of services and data availability1.

The sharing of the Virtual Volume VPD is a critical step in the process of LUN encapsulation behind VPLEX, ensuring that the ESXi cluster can successfully re-discover and utilize the datastore and RDM LUNs.

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.

When considering the use of a VPLEX logging volume, it is important to note that a logging volume must be created on each VPLEX cluster before creating a distributed device. This is because logging volumes play a critical role in the VPLEX architecture by capturing write logs that are essential for data consistency and recovery processes.

Role of Logging Volumes: Logging volumes in VPLEX are used to store write logs that ensure data consistency across clusters, especially in distributed device configurations1.

Creation Before Distributed Devices: Before a distributed device can be created, which spans across clusters for high availability, logging volumes must exist on each cluster to handle the write logging required for the distributed device1.

VIAS and Automatic Provisioning: While VIAS (VPLEX Integrated Array Services) is a tool that simplifies storage provisioning tasks, and automatic provisioning can occur in certain scenarios, the creation of logging volumes is a prerequisite step that typically requires explicit action by the administrator before distributed devices are set up1.

Sequence of Operations: The sequence of operations is such that logging volumes are created first, providing the necessary infrastructure for capturing write logs, followed by the creation of distributed devices that will utilize these logging volumes1.

By ensuring that logging volumes are created on each VPLEX cluster prior to the creation of distributed devices, administrators can maintain the integrity and high availability of data within the VPLEX environment.

For VPLEX for All Flash (VAF), both the VS2 and VS6 models are recommended. Here’s why:

VS2 Model: The VS2 model is a previous generation of VPLEX hardware that supports all-flash configurations.It is designed to handle the high throughput and low latency requirements of all-flash storage1.

VS6 Model: The VS6 is the latest generation of VPLEX hardware, offering enhanced performance and scalability compared to the VS2.It is also suitable for all-flash environments and is designed to leverage the full capabilities of flash storage1.

Upgrade Path: Organizations with existing VS2 hardware can continue to use it for VAF, but they may consider upgrading to VS6 for improved performance and newer features.The VPLEX architecture allows for non-disruptive upgrades from VS2 to VS6, making it a future-proof solution1.

VPLEX Technology: Both VS2 and VS6 utilize VPLEX technology that virtualizes storage across multiple arrays, allowing for seamless data mobility and continuous availability.This technology is particularly beneficial in all-flash environments where performance and uptime are critical1.

Documentation: The Dell VPLEX Operate Achievement documents provide detailed information on the capabilities of both VS2 and VS6 models, including their suitability for VAF environments1.

By choosing either VS2 or VS6 models for VPLEX for All Flash, organizations can ensure they have a robust and high-performing storage virtualization platform that meets the demands of modern all-flash arrays.

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.

The RAID level for a virtual volume on VPLEX is defined at the device stage. Here’s the explanation:

Claimed Volume: This is the initial stage where a physical volume from a storage array is claimed by VPLEX. At this point, no RAID configuration is applied.

Extent: After claiming the volume, VPLEX divides it into extents, which are logical subdivisions of the claimed volume. Extents still do not have RAID configurations.

Device: This is the stage where RAID is applied. A VPLEX device is created from one or more extents, and it is at this point that the RAID level is defined.The device can be configured with various RAID levels, depending on the desired performance and redundancy requirements1.

Storage Volume: The term ‘storage volume’ typically refers to the physical storage on the array before it is claimed by VPLEX. It does not have a RAID level associated with it until it is claimed and turned into a VPLEX device.

By defining the RAID level at the device stage, VPLEX allows for flexibility and resilience in how data is stored and protected across the storage infrastructure.

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.