D-MSS-DS-23 EMC Dell Midrange Storage Solutions Design 2023 Free Practice Exam Questions (2025 Updated)

For optimal iSCSI performance on a Dell Unity XT array, configuring jumbo frames is recommended. Jumbo frames allow for larger packets of data to be sent over the network, reducing the CPU load on both the storage array and the host, and improving overall throughput. Configuring jumbo frames typically involves setting the MTU (Maximum Transmission Unit) to 9000 bytes on all network devices along the path.

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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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During normal operation, a promotion to FAST Cache is initiated after the Policy Engine determines that 64 KB block of data is being accessed frequently. For consideration, the 64 KB block of data must have been accessed by reads and/or writes multiple times within a short amount of time.

Whenonly two SAS ports are available on each Storage Processor (SP) in a Dell Unity XT Disk Processor Enclosure (DPE), therecommended order for connecting DAEsis toalternate DAEs between buses (SAS Bus 0 and SAS Bus 1)to achieve balanced performance and availability.

✅Recommended Order (per Dell EMC Best Practices Guide):

DAE 1→ Connect toSAS Bus 1

DAE 2→ Connect toSAS Bus 0

DAE 3→ Connect toSAS Bus 1

✅Why this order?

Alternating DAEs between buses ensures even distribution of I/O load across the two buses.

It enhances fault tolerance and reduces the risk of performance bottlenecks or single points of failure.

This arrangement follows Dell’s best practice to alwaysbalance the number of DAEs across SAS buseswhenever possible.

❌Why not the other options?

A and D– These do not alternate buses, leading to unbalanced bus usage and potential bottlenecks.

B– Does not balance DAEs evenly across the two buses.

C– Alternates the buses for each DAE, following the recommended best practice for2-port DPE configurations.

✅Documentation Reference:

Dell EMC Unity XT Best Practices Guide– Highlights bus load balancing for optimal performance.

Dell EMC Unity XT Hardware Installation Guide– Provides diagrams and connection orders for DAE cabling.

Dell EMC Unity XT Hardware Overview– Confirms the 2-port DPE recommended configurations.

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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.

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.

 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 provides several tools for monitoring and managing Unity environments, each with specific capabilities for performance analysis, anomaly detection, and proactive maintenance.

CloudIQ:

CloudIQ is a cloud-based application that offers proactive monitoring and anomaly detection for Dell storage environments, including Unity.

It leverages advanced analytics and machine learning to provide insights into system health, performance trends, and potential issues before they impact operations.

Other Tools:

InsightIQ: Primarily used for monitoring Isilon and PowerScale systems, not Unity.

Unisphere: Provides management and monitoring for Unity but lacks the advanced anomaly detection capabilities of CloudIQ.

ArrayconfigAnalyzer: Used for specific configuration analysis and not for continuous proactive monitoring.

Dell Midrange Storage References:

Dell Unity XT documentation and CloudIQ guides provide comprehensive details on the capabilities and benefits of using CloudIQ for proactive monitoring.

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

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.

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ForNAS (Network Attached Storage)connectivity in Dell Unity XT systems,network availability and redundancyare critical. Dell Unity XT’s best practice for providing thehighest network availabilityfor NAS involvescombining Link Aggregation Control Protocol (LACP) with Fail-Safe Networking (FSN).

✅Why Combine LACP and FSN?

LACP (Link Aggregation Control Protocol)allows multiple physical network links to be combined into a single logical link. This increases bandwidth and provides redundancy at the link level.

FSN (Fail-Safe Networking)provides redundancy at the network path level. It allows two network paths (or groups of links) to be configured with one active and one standby group. If the active path fails, FSN automatically switches to the standby path.

✅Best Practice Benefits:

LACP:Improves link utilization and provides protection against link-level failures.

FSN:Protects against broader network path failures, including switch failures or upstream connectivity issues.

Combined Approach:Providesboth link-level and path-level redundancy, ensuring the highest availability and resiliency for NAS workloads.

✅Documentation Reference:

Dell EMC Unity XT Best Practices Guide (Dell Technologies)– Specifically outlines the recommendation tocombine LACP and FSNfor NAS deployments.

Dell EMC Unity XT Networking Guide– Provides configuration examples and detailed explanations for implementing LACP and FSN in a Unity XT NAS environment.

✅Why not the other options?

A. LACP alone– Improves availability at the link level but not for upstream switch or path-level failures.

B. FSN alone– Provides path-level redundancy but lacks link-level load balancing.

D. Multi-pathing software like PowerPath– Primarily used forblock storage (FC/iSCSI), not NAS.

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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 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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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.

SAS Flash 2 drives can be used in a FAST Cache pool configuration for Dell Unity XT solutions. FAST Cache (Fully Automated Storage Tiering Cache) allows frequently accessed data to be moved to high-performance SSDs, improving overall system performance. SAS Flash 2 drives are suitable for this purpose, providing a balance of performance, endurance, and cost. Reference:Dell Unity XT FAST Cache Overview

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InDell Unity XT dynamic pools, when new drives are added to an existing pool, the system automatically integrates these drives into the pool. However,Unity XT dynamic pools only use the capacity of new drives up to the size of the smallest drive in the pool(a concept known ascapacity equalization).

✅What happens here?

The original pool was created with1.92 TB SSD drives.

The administrator adds4 x 3.84 TB SSD drivesto the same pool.

Because the pool’s smallest drive is1.92 TB, the system uses only1.92 TBof capacity from each of the new drives.

The remaining1.92 TBof the new drives’ capacity isnot utilizedin the dynamic pool.

✅Key Takeaways:

This behavior ensures uniform capacity usage across all drives in the pool, maintainingRAID group balance and data distribution.

To fully leverage the 3.84 TB capacity, the administrator would need to create anew poolusing only the larger drives.

✅Documentation Reference:

Dell EMC Unity XT Best Practices Guide (Dell Technologies)– Discusses dynamic pool behavior and drive capacity equalization.

Dell EMC Unity XT Dynamic Pools Technical White Paper– Provides detailed explanations on how dynamic pools manage mixed drive sizes.

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