When troubleshooting SAN performance problems, a key indicator of a physical issue is a high CRC

(Cyclic Redundancy Check) error count. CRC errors are indicative of corrupt data packets during

transmission, which often points to issues such as faulty cables, bad ports, or other physical

problems in the network infrastructure. High CRC error counts can lead to retransmissions, reduced

throughput, and overall degradation of SAN performance. Addressing the physical components

associated with high CRC error counts is essential for restoring optimal SAN operations.

Reference:

While the specific Dell XtremIO Design document was not available, general SAN troubleshooting

guidelines and best practices indicate that CRC errors are a critical metric to monitor for physical

connectivity issues1.

Additional resources on SAN performance troubleshooting can be found in the support

documentation for the XtremIO Family on Dell’s official website2.

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To stay updated with the most recent changes, features, and limits for XtremIO, an administrator

should consult the XtremIO Release Notes. These documents are specifically designed to provide

users with information about the latest updates, including new features, enhancements, fixed issues,

and known limitations that are relevant to the XtremIO storage array systems.

Reference:

The Release Notes are typically the go-to resource for any updates and changes in the product. They

are part of the standard documentation provided by Dell for their products1.

For detailed information on the features and design of XtremIO, the “Dell XtremIO Design

Achievement” document provides insights into the product features, functionality, use cases, and

configurations2.

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When designing an Oracle solution for a customer using XtremIO, it’s important to consider the best

practices for performance and efficiency.

Option OD, “Allocate multiple LUNs per host, Use Thin formatting on the ESXi”, is a recommended

best practice for Oracle environments12.

Allocating multiple LUNs per host can help distribute the I/O load more evenly across the storage

system, which can improve performance1. This is particularly important in Oracle environments,

where there can be a high level of concurrent I/O activity1.

Using Thin formatting on the ESXi is also recommended. Thin provisioning is a storage provisioning

method that optimizes the efficient use of available space. For a thin virtual disk, ESXi provisions the

entire space required for the disk’s current and future activities, but the thin disk uses only as much

storage space as the disk needs for its initial operations3. If the disk requires more space, it can

expand into its entire provisioned space3.

The other options, while they may be part of the overall

Live Optics is a performance capture technology that helps to evaluate cloud candidacy by providing

real-time data collection and visual analysis of an environment’s current workload performance. It is

designed to offer insights into the infrastructure’s capabilities and to identify opportunities for

optimization or migration to cloud services. Live Optics captures, analyzes, and visualizes the

workload characteristics to help organizations make informed decisions about cloud adoption based

on their specific performance metrics and requirements1.

Reference:

The Dell XtremIO Design documents and training materials emphasize the importance of

understanding workload performance and characteristics when considering cloud solutions, which is

facilitated by tools like Live Optics1.

Additional information on the role of performance capture technologies in cloud candidacy

evaluation can be found in the Dell Technologies Education Services resources2.

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For environments expected to grow significantly (more than 150 TB physical capacity), it is better to

start with an X2-R cluster and add additional X2-R X-Bricks as needed. X2-R configurations are

designed for a variety of use cases and can handle larger capacities and high-performance

requirements.

Explore

I/O Elevators refer to the I/O scheduling algorithms used in operating systems to control how I/O

operations are submitted to storage12. These algorithms, also known as elevators, determine the

order in which I/O requests from different processes or devices are serviced by the underlying

hardware, such as hard drives or solid-state drives (SSDs)12. The goal of these algorithms is to

improve the efficiency of data access and reduce the time wasted by disk seeks3.

The other options provided are not typically referred to as I/O Elevators:

Option OB, “The maximum number of consecutive ‘sequential’ I/Os allowed to be submitted to

storage”, refers to a specific parameter of a storage system, not an I/O Elevator4.

Option OC, “Setting which controls for how long the ESX host attempts to login to the iSCSI target

before failing the login”, refers to a specific setting in ESXi host configuration, not an I/O Elevator567.

Option OD, “The amount of SCSI commands (including I/O requests) that can be handled by a storage

device at a given time”, refers to the command handling capacity of a storage device, not an I/O

Elevator89.

Therefore, the verified answer is A. I/O scheduling algorithm which controls how I/O operations are

submitted to storage, as it accurately describes what I/O Elevators are according to the Dell XtremIO

Design Achievement document10 and other sources123.

MPIO (MultiPath I/O) is required for Fast I/O Failure for the AIX operating system as it helps in

managing multiple paths for redundancy and failover.

XtremIO X2 supports configurations starting from a single X-Brick and scaling up to multiple X-Bricks.

However, the X2 system can support up to 8 X-Bricks in a cluster, not just 4, so option D is more

correct.

To accommodate a workload that generates 500,000 IOPS with a maximum bandwidth of 14 GB/s,

the recommended XtremIO X2 solution would be 4 X-Bricks. This recommendation is based on the

specifications that a fully populated X-Brick module with 72 flash drives supports 220,000 IOPS1.

Therefore, to support 500,000 IOPS, more than two X-Bricks are required. Additionally, the

bandwidth requirement of 14 GB/s must be considered, and typically, more X-Bricks can provide

higher bandwidth capabilities.

Reference:

Dell EMC Ready Solutions for Oracle with XtremIO X2 document2.

Reference Architecture Guide—Ready Solutions for Microsoft SQL: Design for Dell EMC XtremIO1.

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