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

Understanding Storage Performance Saturation:

In the Configurations tab of the PowerStore sizing tool, the Storage Performance Saturation field provides crucial information about the overall performance demand placed on the storage solution.

Multi-Appliance Solution Context:

When working with a multi-appliance PowerStore solution, it is important to assess the combined performance demands of all workloads across the appliances.

Aggregate of All Workloads:

The Storage Performance Saturation field shows the aggregate performance demand of all workloads combined. This helps in determining if the current configuration can handle the cumulative IOPS and throughput requirements or if additional resources are needed.

Dell Midrange Storage References:

Dell Technologies documentation on PowerStore and its sizing tools provide detailed guidelines on how to interpret and utilize performance metrics, including the Storage Performance Saturation field.

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.

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 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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Recovery Point ObjectiveWhen you set up an asynchronous replication session, you can configure automatic 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).

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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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In the PowerStore sizing tool, the default Data Reduction Ratio (DRR) values for block and file workloads are Block = 4:1 and File = 2:1. These values represent the expected reduction in data size due to compression and deduplication, which helps in planning the storage capacity and performance requirements effectively. Reference:Dell PowerStore Sizing Tool Documentation

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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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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.