D-MSS-DS-23 Dell Midrange Storage Solutions Design 2023 Question and Answers

DataDobi is a tool that can be used to migrate file data for Windows hosts from a legacy VNX array to a new Dell Unity XT array. DataDobi offers efficient and reliable data migration capabilities, ensuring minimal downtime and data integrity during the migration process.

=================

The maximum number of thin clones per base LUN within Dell Unity XT is 32. Thin clones are efficient copies of a LUN (Logical Unit Number) that share the same underlying storage blocks, allowing for quick and space-saving creation of additional LUNs based on the same data. Reference:Dell Unity XT Thin Cloning Guide

=================

Dell Unity XT and DR Design:

For disaster recovery (DR) within a metro distance and zero Recovery Point Objective (RPO), synchronous replication is the preferred method.

Synchronous replication ensures that data is written to both the source and target volumes simultaneously, which requires high performance to minimize latency.

Best Practices for Minimizing Impact on Performance:

Multiple Ports per Controller: While this can improve throughput, it does not directly minimize the latency impact of synchronous replication.

Flash Tier in Hybrid Pool: Including a flash tier in a hybrid pool enhances performance significantly because flash drives offer lower latency and higher IOPS compared to traditional spinning disks. This is critical for synchronous replication scenarios where performance impact needs to be minimized.

Thick Volumes: Using thick volumes can provide consistent performance, but they do not inherently minimize the impact of synchronous replication.

Synchronous Replication Session: Creating the replication session before filling the source storage object with data is a procedural step and does not address performance during active replication.

Dell Midrange Storage References:

Dell Unity XT best practices emphasize the use of flash tiers in hybrid pools to boost performance for demanding operations, including synchronous replication.

Resources from Dell Technologies' documentation on storage-based replication and performance optimization provide detailed insights.

References:

Dell Unity XT Best Practices

Dell Community on Midrange Storage

Dell Storage Product Information

=================

In a scenario where a customer needs to design a DR site with a 15-minute RPO using storage-based asynchronous replication, creating a single protection policy assigned to 30 volumes with a five-minute shift between each volume is the most stable design. This approach ensures that the replication load is evenly distributed over time, minimizing the impact on storage performance.

Recovery Point ObjectiveWhen you set up an asynchronous replication session, you can configureautomatic synchronization based on the RPO. You can specify an RPO from a minimum of 5 minutes up to a maximum of 1440 minutes (24 htours).

=================

The tool used to remediate issues discovered during a site evaluation is ECT (ESRS Configuration Tool). ECT is a diagnostic and remediation tool provided by Dell that assists in configuring and troubleshooting ESRS (Secure Remote Services), which is essential for proactive monitoring and support of Dell EMC systems. ECT helps ensure that any identified issues during site evaluations are addressed effectively. Reference:Dell ESRS Overview

=================

According to Dell best practices for PowerStore solutions, when supporting hosts that use both 100 Gb/s Ethernet (Eth) connectivity and 16 Gb/s Fibre Channel (FC) connectivity, the I/O modules should be populated as follows:

Slot 0:Install the 100 Gb/s Ethernet I/O module. This ensures that the high-speed Ethernet connections are handled by the first slot, which is typically prioritized for network connectivity.

Slot 1:Install the 16 Gb/s Fibre Channel I/O module. This setup leverages the capabilities of the second slot to manage Fibre Channel traffic efficiently.

This configuration ensures optimal performance and adherence to best practices, providing a balanced distribution of network and storage connectivity within the PowerStore system.

References:

Dell Technologies PowerStore Documentation

Dell Entry-Level and Mid-Range Storage Community

Dell Storage Products Overview

=================

The simple performance path in the Dell Unity XT sizer tool uses predefined configurations to streamline the sizing process.

This path considers various parameters to estimate the achievable IOPS rate and overall system performance.

Drive Busy Percentage:

The simple performance path assumes a maximum of 80% drive busy percentage to determine the achievable IOPS rate.

This threshold ensures that the drives are utilized efficiently without overloading, balancing performance and longevity.

Other Percentages:

Lower percentages (50%, 60%, 70%) would be too conservative and might result in under-utilization of the system’s capabilities.

Dell Midrange Storage References:

Dell Unity XT documentation and sizer tool guides provide detailed information on performance metrics and assumptions used for sizing.

Community forums and support resources from Dell Technologies offer additional insights and user experiences.

References:

Dell Unity XT Sizer Tool Guide

Dell Community on Storage Performance

=================

The NVMe Expansion Enclosure attached to a PowerStore system includes slots for 25 2.5-inch NVMe drives and supports the use of NVMe Storage Class Memory (SCM) drives. These features allow for high-performance storage expansion with low latency and improved efficiency.

The recommended maximum cable length for PowerStore back-end NVMe cabling to avoid performance issues is 10 meters. This recommendation helps to ensure signal integrity and optimal performance across the NVMe interface, which is critical for maintaining the high throughput and low latency characteristics of NVMe storage.

=================

Sizing for PowerStore Solutions:

Accurate sizing for PowerStore solutions requires specific workload parameters to ensure that the storage system meets performance and capacity requirements.

Required Parameters:

IOPS (Input/Output Operations Per Second): A key performance metric indicating the number of read/write operations the system must handle.Essential for determining the required performance capability.

Effective Capacity: The usable storage capacity after considering data reduction technologies like compression and deduplication. Critical for ensuring the system can accommodate the data volume.

Other Parameters:

Response Time: While important for performance, it is not typically required to proceed with sizing.

Data Reduction Ratio: Influences effective capacity but is not a direct input for initial sizing.

Dell Midrange Storage References:

Dell PowerStore documentation provides detailed guidelines on the parameters needed for accurate sizing.

Community forums and support resources from Dell Technologies offer additional insights and best practices.

References:

Dell PowerStore Sizing Guide

Dell Community on Storage Sizing

=================

When sizing a Dell Unity XT solution using the Simple Performance method, parameters such as Read size (KB) and Target IOPS can be defined. The Simple Performance method focuses on understanding the expected IOPS (Input/Output Operations Per Second) and read size to ensure that the system is sized appropriately to meet performance requirements. This approach helps in configuring the storage system to handle the expected workload efficiently.

=================

Asynchronous Replication in Dell Unity XT:

Asynchronous replication provides data protection over longer distances with flexible RPO settings.

Maximum RPO:

The maximum Recovery Point Objective (RPO) that can be configured for a block-asynchronous replication session in Dell Unity XT is 7 days.

This allows for up to a week's worth of data to be replicated asynchronously, balancing data protection and replication overhead.

Other Options:

24 hours, 48 hours, 14 days: These options do not align with the maximum configurable RPO of 7 days for asynchronous replication in Dell Unity XT.

Dell Midrange Storage References:

Dell Unity XT documentation provides detailed guidelines on configuring asynchronous replication and the available RPO settings.

Community forums and support resources from Dell Technologies offer insights into best practices for data protection.

References:

Dell Unity XT Replication Guide

Dell Community on Data Protection

=================

Dynamic Pool Configuration with RAID 5:

RAID 5 (4+1) protection involves 4 data drives and 1 parity drive.

Minimum Drive Count:

For creating a dynamic pool with RAID 5 (4+1), the configuration must include at least 2 RAID 5 (4+1) groups to ensure redundancy and performance.

The minimum drive count for this setup would be 2 * (4 + 1) + 1 (hot spare) = 11 drives.

RAID 5 Requirements:

This configuration ensures that the dynamic pool has enough drives to maintain performance and data protection according to Dell’s best practices.

Dell Midrange Storage References:

Dell Unity XT documentation provides detailed guidelines on RAID configurations and the minimum drive requirements for dynamic pools.

Community forums and support resources from Dell Technologies offer insights into best practices for configuring RAID and dynamic pools.

References:

Dell Unity XT RAID Configuration Guide

Dell Community on Storage Configurations

Understanding CPU Utilization Levels:

Dell Unity XT systems categorize CPU utilization to help administrators assess the performance and health of their storage systems.

Utilization levels typically include categories like low, normal, high, and extremely high to simplify performance monitoring.

CPU Utilization in Dell Unity XT:

According to Dell Unity XT documentation, CPU utilization percentages are used to determine the performance state of the system.

A CPU utilization of 68% is considered high but not critical. This is because the system is handling a significant load but still within operational parameters.

Operational Thresholds:

Low Utilization: Below 30%

Normal Utilization: 30% - 60%

High Utilization: 60% - 80%

Extremely High Utilization: Above 80%

Given these thresholds, 68% falls into the "High Utilization" category.

Dell Midrange Storage References:

Dell Technologies Partner Program documentation on midrange storage provides detailed metrics and thresholds for system performance. This information is crucial for administrators to make informed decisions about system capacity and performance tuning.

Additional resources on Dell's community forums and official product pages for entry-level and midrange storage also support these utilization thresholds.

By categorizing CPU utilization as "High" at 68%, administrators can take necessary actions to optimize system performance or plan for additional capacity if needed.

References:

Dell Unity XT Overview

Dell Entry-Level and Mid-Range Community

Dell Storage Products

=================

The Dell Unity XT 380F array is equipped with converged network adapter (CNA) ports, while the Dell Unity XT 880F array features embedded mezzanine ports. These differences in port configurations reflect the varied performance and connectivity options available in different models of the Unity XT series.

FAST Cache Mechanism:

FAST (Fully Automated Storage Tiering) Cache in Dell Unity systems temporarily holds frequently accessed data to improve read and write performance.

The data moved to FAST Cache is managed in chunks to optimize storage efficiency and performance.

Chunk Size for FAST Cache:

Dell Unity systems use a chunk size of 128 KB for data moved to FAST Cache. This size is optimized for balancing performance and storage management overhead.

Smaller chunks, such as 32 KB or 64 KB, might increase management overhead, while larger chunks like 256 KB could reduce the granularity of data movement and efficiency.

Dell Midrange Storage References:

Dell Unity XT documentation provides detailed explanations on FAST Cache operations, including the specific chunk sizes used.

Additional technical resources from Dell Technologies offer insights into performance tuning and cache management.

References:

Dell Unity XT FAST Cache Guide

Dell Community on Cache Management

Dell Storage Product Information

=================

Connecting ESXi Hosts to PowerStore:

When connecting ESXi hosts to PowerStore, it is crucial to follow best practices to ensure optimal performance and reliability.

Round Robin Multipathing:

Dell recommends configuring Round Robin Multipathing with an IOPS limit of 1024. This setting helps balance the load across multiple paths, preventing any single path from becoming a bottleneck and improving overall performance.

Other Options:

DelayedACK: Generally not recommended for iSCSI configurations due to potential performance issues.

Two NAS Servers for vVol Datastores: Not a standard recommendation for general PowerStore-ESXi connectivity.

Default 8k host I/O size for NFS: Not a specific recommendation for this context.

Dell Midrange Storage References:

Dell PowerStore documentation and VMware integration guides provide detailed best practices for connecting ESXi hosts, including multipathing configurations.

References:

Dell PowerStore Best Practices Guide

Dell Community on PowerStore and VMware

=================

The minimum number of drives in a RAID 5 dynamic pool is 5. RAID 5 requires at least 3 drives for data striping with parity, but Dell's implementation in Unity systems requires a minimum of 5 drives to ensure optimal performance and reliability.

When evaluating an existing Dell Unity XT system configuration, telemetry files can be collected using UEMCLI and unity_telemetry_data collects. UEMCLI (Unisphere Command Line Interface) allows administrators to gather detailed configuration and performance data from the array. Additionally, unity_telemetry_data collects is used to gather comprehensive telemetry data which includes detailed performance and usage statistics crucial for analysis and troubleshooting.

=================

RAID 6 Dynamic Pool Configuration:

RAID 6 provides high data protection by using double parity, allowing for two drive failures without data loss.

Minimum Number of Drives:

A RAID 6 dynamic pool in Dell Unity XT systems requires a minimum of 8 drives to configure. This includes 2 drives for parity and 6 drives for data storage.

Drive Configuration:

The minimum configuration ensures that the system can provide the necessary data protection and redundancy while maintaining performance.

Dell Midrange Storage References:

Dell Unity XT documentation provides detailed guidelines on RAID configurations and the minimum requirements for various RAID levels.

Community forums and support resources from Dell Technologies offer additional insights into RAID setup and best practices.

References:

Dell Unity XT RAID Configuration Guide

Dell Community on RAID Configurations

=================

Dell recommends disabling DelayedACK when configuring ESXi hosts using iSCSI to connect to PowerStore systems. DelayedACK can cause performance degradation and connectivity issues in iSCSI environments. By disabling DelayedACK, the communication between the ESXi host and the PowerStore array becomes more efficient, leading to better performance and reliability.