EMC D-MSS-DS-23 Dell Midrange Storage Solutions Design 2023 Exam Practice Test

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.

Adding 6 x 3840 GB NVMe SSD drives is the most cost-effective way to expand the capacity of a PowerStore 3200T system. This addition provides a significant increase in both raw and usable capacity, offering a better balance of performance and cost compared to smaller or more expensive drive options.

When using theDell Unity XT Sizer Tool(or Dell’s Midrange Sizer), theSystem Designeroption is the one that supports advanced configurations, including hybrid dynamic pools.

✅System Designer Features:

Detailed Sizing– Allows you to customize configurations at a granular level, including disk pool type, RAID configurations, and hybrid dynamic pools.

Hybrid Dynamic Pools– These pools combine SSD and HDD tiers to create a cost-effective and performance-optimized storage environment, which is a typical design for Dell Unity XT systems.

Workload Modeling– Offers more precise performance and capacity recommendations for mixed workloads.

✅Why not the other options?

A. Advanced Performance– This isn’t a standalone sizer option; rather, performance considerations are built into System Designer.

B. Quick Configuration– Designed for fast sizing with minimal inputs, and it doesn’t support detailed hybrid pool configuration.

D. Simple Performance– This is not a recognized option in Dell’s Unity XT sizing tools.

✅Documentation Reference:

Dell EMC Unity XT Sizer User Guide– Outlines the functionality of System Designer and confirms it’s the module to use for hybrid dynamic pool configurations.

Dell EMC Unity XT Best Practices Guide– Confirms that hybrid pools are best configured using detailed sizing, not quick configuration.

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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.

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To provide the best performance on Dell Unity iSCSI connections, configuring Jumbo frames end-to-end is recommended. Jumbo frames allow for larger packet sizes than the standard 1500 bytes, typically up to 9000 bytes. This reduces the number of packets transmitted, decreases CPU utilization, and improves overall network efficiency. Here’s how to configure Jumbo frames:

Switch Configuration:Enable Jumbo frames on all network switches that will handle iSCSI traffic.

Network Interface Configuration:Configure all network interfaces (NICs) on the storage system and the iSCSI hosts to support Jumbo frames.

End-to-End Consistency:Ensure that Jumbo frames are configured consistently across the entire network path from the storage system to the hosts to avoid fragmentation and performance degradation.

SAS Flash 4 drives in Dell Unity XT arrays are rated at 1 write per day. This rating indicates the drive’s endurance level and how many times the entire drive capacity can be written to per day over its warranty period. This level of endurance is designed to balance performance, cost, and reliability for general-purpose workloads.

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When sizing a new Dell Unity XT array that requires hybrid dynamic pools, the "Quick Configuration" option must be selected in the Midrange Sizer. This option streamlines the configuration process, allowing for a balanced and efficient setup of hybrid pools. Here’s why Quick Configuration is used:

Simplifies Setup:Quick Configuration provides a straightforward approach to setting up the array, ensuring that the necessary parameters for hybrid dynamic pools are configured correctly without requiring in-depth manual input.

Balanced Performance:The tool uses predefined settings and best practices to create a hybrid pool that balances performance and capacity, making it ideal for a variety of workloads.

When evaluating an existing Dell Unity XT system configuration,telemetry data(health and performance logs) is crucial for diagnostics and performance analysis. Dell Unity XT providestwo primary methodsfor collecting telemetry files:

✅A. unity_service_data collects

This is a common method using the svc_data command to gather comprehensive logs and telemetry data for Dell Unity XT systems.

The commandcollects service dataincluding health, performance, and diagnostic logs.

It is often used by support engineers and system administrators to troubleshoot and evaluate system health.

✅B. UEMCLI

UEMCLI (Unity CLI) is a command-line interface for managing Dell Unity systems.

It provides commands to collect telemetry and diagnostic information.

For example, you can use commands like:

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uemcli -d -u -p /service/system/collect-service-data

UEMCLI is flexible, scriptable, and often used in automated telemetry collection for system evaluations.

❌Why not the other options?

C. PSTCLI– This CLI is used with PowerStore systems, not Unity XT.

D. unity_telemetry_data collects– This is not a valid or recognized command within Unity XT’s official documentation or CLI reference.

✅Documentation Reference:

Dell EMC Unity: Service Commands and Diagnostics Guide (Dell Technologies)

Dell EMC Unity XT CLI Command Reference Guide (UEMCLI usage)

Dell EMC Unity XT Best Practices Guide– covers recommended methods for collecting and using service data and telemetry files.

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Understanding DRR (Data Reduction Ratio):

The Data Reduction Ratio (DRR) is a measure used in storage solutions to determine the efficiency of data reduction technologies such as deduplication and compression.

In NVMe-based systems like PowerStore, achieving an optimal DRR is crucial for balancing capacity and performance.

Sizing PowerStore Solutions:

When sizing a PowerStore solution, it's essential to align the provided capacity and performance (IOPS) with the customer's requirements.

If the recommended solution vastly exceeds the requested capacity (10 times more in this case), it indicates an overly conservative DRR assumption.

Recommended Action:

The architect should adjust the DRR to reflect a more accurate estimate that aligns with the customer's actual data reduction potential.

This adjustment ensures that the solution is cost-effective and meets the performance criteria without excessive over-provisioning.

Dell Midrange Storage References:

Dell Technologies documentation on PowerStore solutions provides detailed guidelines on DRR configurations and best practices.

Resources include sizing tools, system editor settings, and real-world case studies that illustrate appropriate DRR adjustments.

CloudIQ Mobile App Features:

CloudIQ provides comprehensive monitoring and management for Dell storage platforms, accessible through both web and mobile apps.

Supported Features:

Overview of Health, Capacity, and Performance: The mobile app provides users with an overview of the health, capacity, and performance details for supported Dell storage platforms.

Email Recommended Remediation: The app allows users to email recommended remediation steps to colleagues, facilitating collaboration and resolution of identified issues.

Other Features:

Manage Capacity and Performance Details: While the mobile app provides an overview, detailed management typically requires access through the web interface.

Access Controls and User Roles: Setting up access controls and assigning user roles is generally managed through the primary CloudIQ interface rather than the mobile app.

Dell Midrange Storage References:

CloudIQ documentation and mobile app guides detail the features available to users for monitoring and collaboration.

Community forums and support resources from Dell Technologies provide additional insights into using CloudIQ effectively.

Dell Unity XT offers both synchronous and asynchronous replication to protect data and ensure business continuity.

Synchronous replication is used for zero RPO, ensuring no data loss, but it is typically limited to shorter distances due to latency concerns.

Asynchronous replication is suitable for longer distances and provides near real-time data protection with a minimal RPO.

Distance Considerations:

The distance between Boston and Cambridge (8 km) is suitable for synchronous replication, providing zero RPO.

The distance between Boston and New York (342 km) is better suited for asynchronous replication due to latency, ensuring data recovery with a minimal RPO, such as 15 minutes.

Optimal Replication Strategy:

Synchronous replication from Boston to Cambridge ensures zero RPO for critical data protection.

Asynchronous replication from Boston to New York provides additional data protection with a 15-minute RPO, suitable for longer-distance disaster recovery.

Dell Midrange Storage References:

Dell Unity XT documentation and best practices provide detailed guidelines on configuring synchronous and asynchronous replication.

Community forums and support resources from Dell Technologies offer insights into real-world implementation strategies.

SAS Flash 3 drives(also known asRead-Intensive (RI)SSDs in Dell Unity XT environments) are typically rated at3 Drive Writes Per Day (DWPD).

✅What does 3 DWPD mean?

It means that these drives are designed to safely handle writingthree times their entire capacity every dayover their warranty period (usually 5 years).

For example, a 1TB SAS Flash 3 drive can handle up to3TB of writes per daywithout exceeding its endurance specification.

✅Why is this important?

The DWPD metric is a crucial factor in determining whether a drive’s endurance matches the expected workload.

3 DWPDstrikes a balance betweenenduranceandcostin most general-purpose storage workloads.

✅Where is this documented?

TheDell EMC Unity XT Best Practices Guideand theDell EMC Unity XT Drive Specification Guidedetail the DWPD ratings for different flash drive types, including SAS Flash 3 drives.

Dell’s documentation confirms that SAS Flash 3 drives (RI SSDs) are rated at3 DWPD.

When sizing Dell Unity XT storage solutions, avoiding bottlenecks and improving performance can be achieved by considering the following parameters:

Port Utilization:Ensuring that the storage system’s ports are utilized efficiently helps in distributing the workload evenly across available resources, preventing any single port from becoming a bottleneck.

Workload Types:Understanding and categorizing different workload types (e.g., random vs. sequential, read vs. write) allows for better allocation of resources and tuning of the storage system to handle specific performance requirements.

Before designing a storage solution, a solution architect must gather comprehensive information to ensure the system meets the customer’s needs. The critical information includes:

Network Infrastructure:Understanding the existing network setup, including LAN and WAN configurations, is essential. This information helps in planning how the storage solution will integrate with the current network and support data traffic efficiently.

Storage Requirements:Detailed knowledge of the storage needs, including capacity, performance, and redundancy requirements, is crucial. This includes understanding the types of data to be stored, the expected data growth, and any specific storage technologies or features the customer may need.

Customer Workload Performance Requirements:Insight into the customer's workload characteristics, such as IOPS (Input/Output Operations Per Second), throughput, latency requirements, and peak usage times, is vital. This information helps in designing a storage solution that can handle the expected workloads without performance bottlenecks.

By gathering this information, the solution architect can design a tailored storage solution that meets the customer’s performance and capacity needs while integrating seamlessly with their existing infrastructure.

The issue arises because File Operations were entered into the PowerSizer tool, but MiB/s (Megabytes per second) was not entered. This causes the tool to translate File Operations into IOPS (Input/Output Operations Per Second) for the cluster and appliance summary details, but since MiB/s was not entered, it does not impact the summary throughput (MiB/s). Here’s the detailed explanation:

File Operations Entry:When file operations are entered, the tool calculates the corresponding IOPS to summarize the workload's impact on the system.

MiB/s Entry Missing:If the MiB/s value is not provided, the tool cannot incorporate this metric into the overall summary, leading to a mismatch where IOPS are calculated but do not affect the MiB/s summary.

The maximum throughput per port in backend 12 Gb SAS (Serial Attached SCSI) ports in Dell Unity XT arrays is 2500 Mbps. SAS ports are used to connect storage devices and provide high-speed data transfer capabilities:

12 Gb SAS Standard:The 12 Gb SAS standard supports high data transfer rates, making it suitable for enterprise storage systems that require robust performance and reliability.

Performance Metrics:Each 12 Gb SAS port can achieve up to 2500 Mbps, which translates to approximately 2.5 Gbps of throughput, supporting high-performance storage operations.

The commandsupportshowis used to gather comprehensive data from Brocade switches. This command collects extensive diagnostic information about the switch, including configuration details, hardware status, and various operational statistics. Here's a step-by-step explanation of thesupportshowcommand:

Access the Brocade Switch:Connect to the Brocade switch via SSH or through a console connection.

Enter the Command:Typesupportshowin the command line interface (CLI) and press Enter.

Data Collection:The command will begin collecting a wide array of information from the switch. This includes:

Hardware and firmware versions

Port status and configurations

Zoning information

Error logs and statistics

Environmental data (temperature, power supply status, etc.)

Output Review:The gathered data is typically extensive and can be used for troubleshooting, performance analysis, and ensuring the switch is operating correctly.

Save the Output:The output can be redirected to a file for later review or analysis by technical support teams.

CloudIQ is a cloud-based application that provides frequent, dynamic, and nondisruptive content updates to users. It offers proactive monitoring, predictive analytics, and detailed health scores for Dell storage environments, including PowerStore and Unity systems. CloudIQ helps users maintain optimal system performance by delivering real-time insights and alerts about potential issues before they impact operations. Here’s how CloudIQ benefits users:

Frequent Updates:CloudIQ continuously gathers and analyzes data from connected systems, providing up-to-date information and insights.

Dynamic Content:The tool dynamically adapts to changing conditions in the storage environment, offering relevant recommendations and updates.

Nondisruptive:All updates and insights provided by CloudIQ are nondisruptive, ensuring that there is no interruption to the system’s operations.

 https://www.dell.com/support/manuals/en-id/unity-600/unity_p_replication_config/about-replication?guid=guid-ccd6033f-680e-47ca-bf91-fa3d4221f9d3 &lang=en-us

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Dell PowerStore supports media devices that carry a FIPS Type D certification to ensure data security and compliance with Federal Information Processing Standards (FIPS). The certified media devices include:

SAS SSD:Serial Attached SCSI (SAS) Solid State Drives are commonly used in enterprise storage solutions for their reliability and performance.

NVMe SSD:Non-Volatile Memory Express (NVMe) Solid State Drives offer high-speed storage access and are optimized for performance.

NVMe SCM:NVMe Storage Class Memory provides a new tier of storage that bridges the gap between DRAM and traditional SSDs, offering both speed and persistence.

NVRAM:Non-Volatile Random Access Memory combines the speed of RAM with the persistence of flash storage, ensuring data is retained even after power loss.

These devices are FIPS Type D certified, ensuring they meet stringent security standards for data protection.

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.