EMC Dell Midrange Storage Solutions Design 2023 D-MSS-DS-23 Exam Dumps: Updated Questions & Answers (October 2025)

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.

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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Step-by-Step Verification:

PowerStoreX Architecture Overview:PowerStoreX is a hyperconverged (HCI) variant of PowerStore that integrates VMware ESXi. Each node requires dedicated IP addresses for:

Management (vCenter, ESXi hosts)

Storage networks (vMotion, vSAN, replication)

Appliance services (cluster communication, data services)

Minimum IP Requirements per Node:According to the Dell PowerStoreX Deployment Guide:

*"Each PowerStoreX node requires 6 IP addresses for optimal operation:

ESXi management (1)

vMotion (1)

vSAN traffic (2 ports, 2 IPs)

PowerStore appliance management (1)

PowerStore cluster/internal communication (1)"*(Section: Network Planning > IP Address Requirements)

Why Fewer IPs Degrade Performance:

4 IPs (Option B): Forces service consolidation (e.g., sharing vSAN/vMotion on one interface), causing network congestion.

7/9 IPs (Options A/D): Support advanced configurations (e.g., replication/NFS) but not the minimum for baseline optimization.

Validation from Sizer and Best Practices:The PowerStore Sizer Tool enforces 6 IPs per node during design:PowerStoreX Sizer IP validation*Source: Dell PowerStore Sizer (v3.6+), PowerStoreX workflow*

Key Dell Documentation References:

Dell PowerStoreX Deployment Guide

"6 IP addresses per node are required to ensure isolation of management, storage, and cluster traffic for optimal performance."

(Table: Minimum Network Requirements per Node)

Dell PowerStoreX: Best Practices Guide

"Assign dedicated IPs to vSAN (2), vMotion (1), ESXi mgmt (1), and PowerStore services (2). Fewer than 6 IPs risks network saturation."

(Section: Network Design)

Dell KB Article #000194532

*"PowerStoreX requires 6 IPs/node minimum. Reducing this causes packet drops under load and violates support SLAs."*

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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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SSD Wear Alerts in Unity XT:

Dell Unity XT systems monitor SSD wear and issue alerts at various intervals (180, 90, 60, and 30 days) before the predicted end of life.

Action at 30 Days:

At the 30-day alert, the system automatically initiates Proactive Copy Operations to copy data from the wearing SSD to a spare drive, ensuring data integrity and continuity.

Proactive Copy Operations:

This proactive measure helps prevent data loss and maintains system performance by preparing for SSD replacement in advance.

Dell Midrange Storage References:

Dell Unity XT documentation provides detailed guidelines on SSD wear monitoring and the associated proactive measures.

Community forums and support resources from Dell Technologies offer additional insights into system maintenance and proactive data protection.

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.

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.

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.

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