Introduction

\\PHYSICALDRIVE0, \\PHYSICALDRIVE1, and \\PHYSICALDRIVE2. The number is assigned during the disk discovery part of the Windows boot process.

During boot-up, the Windows OS loads the driver for the storage HBAs. After loaded, the OS performs a SCSI Inquiry command to get information about all of the attached storage devices. Each disk drive that it discovers is assigned a number in a semi-biasedfirst come, first serve fashion based on HBA. (Semi-biasedmeans that the Windows system always begins with the controller in the lowest-numbered PCI slot where a storage controller resides. After the driver for the storage controller is loaded, the OS selects the adapter in the lowest-numbered PCI slot to begin the drive discovery process.)

It is this naming convention and the process by which drives are discovered that makes persistent binding (by definition) impossible for Windows NT/Windows 2000/Windows 2003. Persistent binding requires a continuous logical route from a storage device object in the Windows host to a volume in an EMC storage array across the fabric. As mentioned above, each disk drive is assigned a number in a first come, first serve basis. This is where faults can occur.

Example Imagine this scenario—A host system contains controllers in slots 0, 1, and 2. Someone removes a cable from the QLogic controller in host PCI slot 0, then reboots the host.

During reboot, the Windows OS loads the QLogic driver during reboot and begins disk discovery. Under the scenario presented above, there are no devices discovered on controller 0, so the OS moves to the controller in slot 1 and begins naming the disks it finds, starting with \\PHYSICALDRIVE0. Any software applications that were accessing \\PHSYICALDRIVE0 before the reboot will be unable to locate their data on the device, because it has changed.

The following figure shows the original configuration before the reboot. HBA0 is in PCI slot 0 of the Windows host. Each HBA has four disk devices connected to it, so Windows has assigned the name \\PHYSICALDRIVE0 to the first disk on HBA0. Each disk after that is assigned a number in sequence as shown in the figure.

Understanding Persistent Binding in a Fabric Environment

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EMC QLogic manual Understanding Persistent Binding in a Fabric Environment

QLogic specifications

EMC QLogic is a leading provider of advanced networking solutions, primarily known for its high-performance storage area network (SAN) technologies. It specializes in Fibre Channel and Ethernet networking products, offering robust solutions that are essential for modern data center environments.

One of the key features of EMC QLogic is its exceptional performance in high-speed data transfer. QLogic's Fibre Channel products, such as switches and host bus adapters (HBAs), support speeds of up to 32 Gbps, ensuring ultra-fast communication between storage devices and servers. This high throughput is crucial for applications demanding high IOPS (Input/Output Operations Per Second), particularly in virtualized environments and databases.

Another prominent aspect of EMC QLogic's technology is its support for advanced features like Data Center Bridging (DCB). DCB enables the convergence of storage and traditional Ethernet traffic on a single network, streamlining data center management and reducing costs. By allowing both storage and data networking to coexist on the same infrastructure, EMC QLogic enhances efficiency and simplifies network architecture.

Scalability is another characteristic that sets EMC QLogic apart. The architecture is designed to support a wide range of deployment sizes, from small businesses to large enterprise data centers. This scalability ensures that organizations can grow their IT infrastructure without needing to overhaul their existing deployment.

EMC QLogic also places a strong emphasis on reliability and security. Their products are built with redundancy and failover mechanisms, which minimize downtime and ensure continuous operation even in the event of hardware failure. Additionally, security features such as encryption and access controls are integrated to protect sensitive data as it travels across the network.

Management and monitoring capabilities are also integral to EMC QLogic's offerings. The company provides advanced software tools for managing network resources, allowing administrators to monitor performance, diagnose issues, and optimize configurations efficiently. This helps organizations maintain peak performance and reduces operational complexity.

In summary, EMC QLogic combines high-speed performance, advanced features, and robust reliability in its networking solutions. With a focus on scalability and security, it provides organizations with the tools necessary to build and manage efficient, modern data centers that can adapt to evolving technological demands. Its commitment to innovation positions EMC QLogic as a trusted partner in the storage networking landscape.