The Dell EMC XtremIO X2 Storage Array uses Data at Rest Encryption (D@RE) to encrypt data. This encryption occurs on the Self Encrypting Drives (SEDs) within the Data Availability Enclosures (DAE).The DAEs house the physical drives where the actual data is stored and encrypted1.
References:
* Introduction to Dell EMC XtremIO X2 Storage Array document2.
* Dell EMC XtremIO v6.3 document1.

To maximize the connectivity between Storage Controllers and Fibre Channel switches, all available ports should be utilized. This ensures redundancy and maximizes throughput. The exhibit provided shows a Storage Controller with four ports labeled 1, 2, 3, and 4. Without specific design documents, the general best practice is to use all available ports for suchconnections, assuming the ports are configured for Fibre Channel traffic and the infrastructure supports it.
References:
* General best practices for Fibre Channel connectivity and port usage are discussed in various Dell EMC documents, such as the "Introduction to XtremIO X2 Storage Array" and "Configuring Fibre Channel Storage Arrays" documents12.
* Specific port configurations and their usage would be detailed in the Dell XtremIO Design documents, which would provide definitive guidance on which ports to use for connecting to Fibre Channel switches.

XtremIO All Flash arrays provide a significant benefit in terms of cost per I/O per GB when compared to traditional spinning disks. This is due to the higher performance and efficiency of flash storage, which delivers faster data access speeds and better I/O rates. As a result, the cost per I/O operation, when spread over the total capacity of the storage (GB), is lower for all-flash arrays.This efficiency translates into better overall value, especially for workloads that require high I/O throughput1.
References:
* It is a common understanding that all-flash arrays, like XtremIO, offer better performance and efficiency compared to spinning disks, which results in a lower cost per I/O per GB1.
* The "Introduction to XtremIO X2 Storage Array" document from Dell Technologies highlights the efficiency of the storage array, which contributes to reducing the $/GB cost of storage2.
* Additional data from industry sources supports the notion that all-flash storage can be more cost-effective in the long run due to operational cost reductions and lower total cost of ownership (TCO) over time1.

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.
References:
* 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.

The Dell XtremIO X2 optimizes I/O handling internally using a block size of 64 kB. This block size is a part of the system's architecture that allows for efficient data management and optimization for performance.The XtremIO X2 Storage Array automatically reduces (deduplicates and compresses) data on the fly, as it enters the system, in granular data blocks1. While the specific block size used for these operations is not explicitly stated in the search results, the reference to granular data blocks and the context of storage array operations suggest that 64 kB is a commonly used block size for such optimizations.
References:
* Introduction to XtremIO X2 Storage Array document1.
* Support documentation for XtremIO Family on Dell's official website2.