Q-Logic 5000 manual Multiple Chassis Fabrics, Optimizing Device Performance

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3 – Planning Multiple Chassis Fabrics

3.5

Multiple Chassis Fabrics

By connecting switches together you can expand the number of available ports for devices. Each switch in the fabric is identified by a unique domain ID, and the fabric can automatically resolve domain ID conflicts. Because the Fibre Channel ports are self-configuring, you can connect SANbox 5000 Series switches together in a wide variety of topologies.

You can connect up to four SANbox 5000 Series switches together through the 10-Gbps ports, thus preserving the user ports for devices. This is called stacking. SANbox 5000 Series switches divide the 10-Gbps port buffer to balance traffic across the connection. The 10-Gbps ports operate with any standard XPAK interface. If the 10-Gbps ports are not active, you can connect SANbox 5000 Series switches with other switches through the 1/2/4-Gbps ports in a wide variety of topologies. Consider your topology and cabling requirements.

3.5.1

Optimizing Device Performance

When choosing a topology for a multiple chassis fabric, you should also consider the locality of your server and storage devices and the performance requirements of your application. Storage applications such as video distribution, medical record storage/retrieval or real-time data acquisition can have specific latency or bandwidth requirements.

The SANbox 5000 Series switch provides the lowest latency of any product in its class. Refer to “Performance” on page 3-3for information about latency. However, the highest performance is achieved on Fibre Channel switches by keeping traffic within a single switch instead of relying on ISLs. Therefore, for optimal device performance, place devices on the same switch under the following conditions:

„Heavy I/O traffic between specific server and storage devices.

„Distinct speed mismatch between devices such as the following:

‰A 2-Gbps server and a slower 1-Gbps storage device

‰A high performance server and slow tape storage device

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