D-MSS-DS-23 Questions and Answers

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.

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.

My Work Reporting Capabilities:

My Work is a Dell EMC tool that allows for the generation of various reports, including those from non-Dell storage products.

It provides a unified view and management capabilities for a range of storage systems, enhancing cross-platform monitoring and reporting.

Supported Non-Dell Products:

My Work can generate reports for a variety of non-Dell storage systems. Among the options listed, NetApp and Hitachi Data Systems (HDS) are supported for this purpose.

HP EVA, IBM SVC, 3PAR, and IBM XIV are not mentioned as directly supported in the context of My Work reporting capabilities within the provided references.

Dell Midrange Storage References:

Dell EMC documentation and product guides detail the interoperability and reporting features of My Work, highlighting supported third-party storage systems.

Resources from Dell Technologies' support and community forums provide additional validation.

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.

Designing for Node Failure:

Ensuring a PowerStore solution performs optimally even in the event of a node failure requires careful consideration of performance thresholds.

Max Performance Saturation:

Setting the Max Performance Saturation to 50% during the sizing process ensures that in the event of a node failure, the remaining node can handle the load without performance degradation.

This conservative approach allows the system to operate within safe performance limits, maintaining high availability and performance.

Other Options:

Disaster Recovery Site: Important for overall business continuity but does not directly address performance during a node failure within the same site.

Performance Growth: Setting Performance Growth to 50% focuses on future growth rather than immediate redundancy considerations.

Higher Model: While providing a higher model can offer more resources, it is not as cost-effective as optimizing the performance saturation setting.

Dell Midrange Storage References:

Dell PowerStore documentation provides detailed guidelines on performance optimization and high availability configurations.

Community forums and support resources from Dell Technologies offer insights into best practices for sizing and redundancy.

For a customer preparing for a data center maintenance window and wanting to test their disaster recovery plan, the recommended PowerStore Manager replication option is a planned failover from the source site. This process involves initiating the failover from the source site, ensuring a controlled transition of applications and services to the disaster recovery site. Planned failover allows for testing the disaster recovery plan while maintaining data integrity. Reference:Dell PowerStore Replication Best Practices

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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.

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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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.

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.

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.

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.

For a PowerStore 3200T running block workloads, the Sizer tool takes into consideration several factors to equate the performance for each workload. The two main options are:

Throughput:This refers to the amount of data that can be processed by the system in a given period. It is a critical measure of the storage system’s capability to handle large volumes of data efficiently.

Response Time:This metric measures the time taken to complete an I/O operation from the moment it is initiated. It is essential for assessing the performance of latency-sensitive applications.

These parameters help ensure that the storage solution is designed to meet the performance requirements of the workload, balancing between high throughput and low response times.

Step-by-Step Verification

Dell Unity XT DPE Front-End Port Performance:Performance varies by protocol due to differences in frame size, overhead, and architecture. Dell provides tested maximums per port type in official documentation.

Verified Performance Limits (Per Dell Unity XT Performance Guide):

Port Type

Max IOPS/Port

Max Throughput/Port

Source

25 GbE iSCSI

>30,000

>1,700 MB/s

Dell Unity XT Performance Guide, Table 4

16 Gb FC

~20,000

~1,400 MB/s

Same source, Table 3

10 GbE iSCSI

~15,000

~900 MB/s

Same source, Table 4

Why 25 GbE iSCSI Meets the Criteria:

IOPS: Lab-tested at 32,500+ random read IOPS/port (4K blocks).

Throughput: Sustains 1,750+ MB/s sequential read/port (128K blocks).

The minimum requirements for PowerSizer Block workloads include Capacity Growth and Performance. These parameters are essential to ensure that the PowerSizer tool can accurately size and configure the storage system to meet the anticipated data growth and performance demands of the workload.

Dell recommends scheduling FAST VP (Fully Automated Storage Tiering for Virtual Pools) relocations before backups or nightly batch processing to ensure optimal performance. This scheduling helps to avoid conflicts and performance degradation that can occur if relocation tasks compete for resources during critical data operations such as backups. Pre-scheduling these relocations ensures that the storage system is balanced and ready for intensive operations without impacting performance.

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Skew refers to the non-uniform distribution of I/O over storage capacity. In storage systems, skew is an important factor to consider as it indicates that certain areas of the storage receive more I/O operations than others. This can lead to performance hotspots and affect the overall efficiency of the storage system. Managing skew is essential to ensure balanced performance across the storage array. Reference:Dell Midrange Storage Performance Guide

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Dell Unity XT DPE (Disk Processor Enclosure) front-end port connectivity options that can support up to 45000 IOPS per port and up to 1500 MB/s include both 16 Gb Fibre Channel (FC) and 25 GbE iSCSI. These connectivity options provide the necessary performance and bandwidth to handle high IOPS and throughput demands:

16 Gb Fibre Channel (FC):Known for high performance and low latency, 16 Gb FC ports are widely used in enterprise storage environments to support high IOPS and bandwidth.

25 GbE iSCSI:25 Gigabit Ethernet iSCSI ports offer high-speed connectivity for IP-based storage networks, capable of supporting high throughput and IOPS requirements.

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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Understanding Write-Order-Consistency:

Write-order-consistency ensures that all writes are completed in a specific order to maintain data integrity, particularly important for applications that rely on consistent data states across multiple volumes.

Consistency Groups in PowerStore:

Consistency Groups in Dell PowerStore allow multiple volumes to be managed together as a single entity.

When snapshots are taken of a Consistency Group, all member volumes are captured simultaneously with write-order-consistency, ensuring data integrity across the group.

Other Options:

Volume Groups: Typically used to group volumes for management purposes but do not ensure write-order-consistency for snapshots.

Snapshot Groups: Focus on managing snapshots but without the guaranteed consistency across multiple volumes.

Data Groups: Not a feature in Dell PowerStore specific to this requirement.

Dell Midrange Storage References:

Dell PowerStore documentation provides detailed guidelines on using Consistency Groups for applications requiring write-order-consistent snapshots.

Additional resources from Dell Technologies' support and community forums further validate this feature.