EMC Updated D-MSS-DS-23 Exam Questions and Answers by leighton

When designing a system to support an Oracle OLAP (Online Analytical Processing) Workload for a new customer without specific I/O details, the default selections for the I/O profile input in the sizer tool are typically set to "Random Read: 70% at 8 KiB, Random Write: 30% at 8 KiB." Here’s a detailed explanation:

Oracle OLAP Workload Characteristics:OLAP workloads generally involve heavy read operations with a focus on retrieving and analyzing large datasets. The read operations are often random due to the nature of querying various parts of the data.

Default I/O Profile Selection:

Random Read:70% - This reflects the high read intensity typical of OLAP workloads, where data is accessed non-sequentially.

Random Write:30% - Although less frequent than reads, writes still occur randomly as new data is added or existing data is updated.

Sizer Tool Configuration:The Dell sizer tool uses these default I/O profile settings to estimate the required storage performance and capacity. This helps in designing a system that can handle the expected workload efficiently.

Performance Optimization:The chosen I/O profile ensures that the storage system is optimized for the specific access patterns of OLAP workloads, providing a balanced approach to handling both reads and writes.

References:

Dell Technologies PowerStore Documentation

Dell Entry-Level and Mid-Range Storage Community

Dell Storage Products Overview

By understanding the default I/O profile settings used by the sizer tool, system designers can ensure that the storage solution is well-suited to meet the demands of Oracle OLAP workloads.

=================

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.

References:

Dell PowerStore Performance Guide

=================

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

=================

Dell recommends disabling DelayedACK when configuring ESXi hosts using iSCSI to connect to PowerStore systems. DelayedACK can cause performance degradation and connectivity issues in iSCSI environments. By disabling DelayedACK, the communication between the ESXi host and the PowerStore array becomes more efficient, leading to better performance and reliability.