Guide-level switches help you achieve SAN Integration

VswitchThe high-end series isGuideGenerally, it refers to a vswitch at the pilot level. The guide is designed and built to achieve scalability and high availability. The term "pilot" was derived from the ibm escon pilot concept in the early 1990s s, the first version used for storage swap devices on large computers. In the early days, many vendors were able to provide FC directors. With the merger and acquisition, the FC directors market has been reduced to two major suppliers, brocade and Cisco.

The switch device connecting the host server and storage system is the core of All Optical Fiber Channel Storage Area Network fc san. The switch device is responsible for the basic connection between FC devices, and is also responsible for determining the type of the connected FC device. The FC partition function is to expand the storage network, two basic types of FC switches are allowed to connect to other fiber channel switches, namely, "directors" and "switches ". Although they all perform the same basic functions, there are significant differences between the two types of switches.

A basic FC switch usually has a fixed number of interfaces and provides basic switching functions. The switch has limited scalability and redundancy. Brocade communication systems, Cisco Systems, and QLogic can now provide this type of FC switch.

Guide Definition

The fundamental difference between the FC switch and the FC guide architecture is that the FC guide is designed and built for expansion to provide high bandwidth and high availability. Today's FC directors are designed with blades to add ports as needed by inserting blades. Currently, the pilot company can expand to several hundred Fiber Channel ports by adding blades containing different numbers of ports in a unit.

Brocade's DCX Backbone series directors can be deployed in a single or dual-Chassis configuration. A single chassis can support up to 384 FC ports, alternatively, the maximum number of FC ports is 768 in the dual-Chassis configuration. DCX-4S is a small version of the brocade DCX product line that can be expanded to 192 ports. The Brocade DCX Backbone guide allows you to increase the number of ports by inserting 16, 32, and 48 blades that support 8 Gbps fiber channels. The Brocade 48000 guide is a product of the previous generation that only supports single chassis configurations and does not have the local switch capability of DCX Backbone.

The Cisco MDS 9500 series multilayer guide has three models: 9506, 9509, and 9513, which can be expanded to 192,336 and 528 ports respectively. Depending on the 4 Gbps or 8 Gbps Optical Fiber Channel, you can add ports for the Cisco MDS 9500 series in different increments. For 4 Gbps FC, Port 12, port 24, or port 48 is incremental. For 8 Gbit/s FC, the increment is 24 and 48 ports, or a 4/44 model that combines four 8 Gbit/s ports and 44 4 Gbit/s ports.

In contrast, a common Fiber Channel Switch usually has a fixed number of physical ports, but the number of activated ports can be reduced by the license key to keep the initial low purchase cost. The number of ports of these vswitches ranges from 8 to 64. The Brocade switch can have up to 80 ports, and the QLogic 9000 can support 128 ports in a single vswitch chassis.

Another benefit of the guide is to provide a large number of ports in a single system, so that you can design a SAN network with at least or no ISLs between switches. ISLs, also known as "Number of hops", may lead to latency, and may degrade performance if it is not the best configuration. When deploying a SAN, a small fixed port switch is often selected. As storage grows, a single vswitch is insufficient and a second vswitch is added. The two vswitches use ISLs to expand the SAN network. As it continues to grow, a third vswitch will be added. This is composed of many small switches. Each switch has several methods dedicated to ISLs interfaces, and many interfaces are not used as device interfaces to connect hosts and storage systems ), the host servers at one end of the SAN must be connected to the storage devices at the other end. The pilot can alleviate this situation by eliminating many or all ISL. Most switch ports can be used to connect devices instead of dedicated ports for the switching architecture.

The guide provides more bandwidth

For an environment that requires high I/O bandwidth, bandwidth is another major advantage of a pilot-level switch. The Brocade DCX Guide provides a total bandwidth of up to Gbps for each 16, 32, or 48-port slot blade. DCX also provides Local switching capabilities to provide a bandwidth of up to Gbps in the same port group with 48 blades. In the Cisco 9500 series, 96 Gbps or Gbps bandwidth is available for slots or switching modules per 24 or 48 ports. The performance data provided by each vendor for their products shows that their products have good working ability under heavy load, but the most important thing is that, these products can handle heavy storage I/O traffic.

In addition, the guide has multiple 10 Gbit/s Fiber Channel interfaces and can be used for ISL trunk links between switches or directors. This ISL function allows you to build a large SAN network from the core to the edge type. One or more directors are located at the SAN core, and a small number of switches with fixed ports are located at the SAN edge. With the popularization of server virtualization, the load on physical servers will increase, and the demand for high bandwidth of FC infrastructure will also increase. The pilot has become a more attractive choice than ordinary switches.

High Availability of the Guide

High Availability is another design feature of the Guide. Usually, the pilot is deployed in a critical business environment, which uses a high normal running time as one of the key criteria of SLA. Generally, the guide is equipped with redundant components to avoid spof. This includes the most basic hot swapping power and fan like redundancy, redundant core processing and switching components, and redundant World Wide NameWWN cards. These high availability features allow uninterrupted software/firmware upgrades.

Some redundant components run in Master/Slave Mode. One component is in active mode, and the other is in standby mode. The other is ready to take over when the active component fails. If a hardware fault occurs on an interface or interface card of the guide, you can remove and replace the interface card without losing the entire Guide. For a fixed port number switch, the same fault usually has to cause the switch to be shut down for repair and replacement. The pilot is designed to maintain and run so that the host server will not be able to access the data stored in it. Of course, all high-availability features will increase system costs.

High-end features of the Guide

The Guide also provides many advanced functions that are unavailable on small fixed port number switches. Both brocade and Cisco directors support virtual SAN, FICON for the mainframe, and remote connection using FCIP, iSCSI, dense wavelength division multiplexing (DWDM), SONET, and other protocols. When comparing the products of the two vendors, the specific implementation methods are slightly different, and these directors used for complex SAN Core can not only process local FC traffic, it can also send FC traffic across regions to remote sites.

Since they adopt a modular design, the Guide can adapt to new requirements. For example, the special blade can support connection to dark fiber, hardware encryption, 10 Gb Ethernet 10GbE), Ethernet Fiber Channel FCoE) and other currently available features, and under the same infrastructure, the design of the Guide also supports future demands without replacing the entire unit.

The management of directors and SAN networks is crucial. These directors provide solid management software to achieve performance monitoring, QoS, and bottleneck detection, advanced partitioning and various other functions. The browser can also use the SNMP protocol to send management data to a higher-level management software platform.

Fiber Channel switches and directors are generally not directly purchased from the manufacturer, but are usually purchased by the server vendor, storage vendor, system integrator, or VAR. Price depends on many factors, including the relationship between you and your suppliers. The guide is expensive, not only because of hardware, but also license keys. The cost of each port of the fully loaded guide is higher than that of a fixed number of fully loaded interfaces switch with the same number of interfaces. The price ratio is about or higher, but the use of the Guide provides better scalability; the Guide has more features such as embedded high availability.

For some data centers, available power is a problem because their power companies say they cannot use any additional power to handle peak workloads. In this case, the data center declares that more energy-saving devices are required.

Like most IT equipment manufacturers, switch and guide manufacturers are focusing on how to save energy. Make the Guide have the ability to integrate several or more common switches, and migrating to the Guide will bring power-saving benefits, so you can expect the guide vendors to emphasize their "green" function.

Do you need a guide?

Before using the Guide to replace your existing exchange infrastructure, you must clarify your requirements. If you need the following, you should consider buying a vswitch at the pilot level:

Each component of the fiber channel infrastructure is highly available, with a high number of ports, a high total bandwidth, and a low proportion dedicated to ISL ports. To determine your specific needs, you must perform some technical analysis, however, if your requirements point to one or more of the above, the browser may be a good solution.

The balance between using a guide or a small fixed port number switch will affect your device budget and operation budget. As described in this article, the guide is more expensive, but can provide more functions. However, you also need to consider the daily management of your fiber channel infrastructure. Are you spending a lot of time managing "things "? Do you think it is easier to manage a large thing than to manage a few items?

You should also consider whether your storage infrastructure is in the growth mode. If you need to add a considerable number of ports now and in the near future-all in the same SAN. In this case, adding a port pilot is a good choice. If you want to increase the number of ports using a small, fixed port number switch, you also need to count the ports dedicated to ISL, rather than the number of storage devices and servers.

As mentioned above, if you select one or more directors, you can still use a small fixed Port Number Switch replaced by the pilot. You can use these vswitches as edge switches and place them close to servers and storage systems in simple core and edge topologies, you can also use these small switches to create an independent test environment.

Generally, deploying vswitches and directors from the same manufacturer has two benefits. First, the manufacturer can guarantee full compatibility with its own devices. Secondly, you may have invested time, experience, and money in training to adapt to a vswitch of a brand. It will be easy to adapt to a guide with similar appearances and feelings, instead of spending time and money learning new devices.

The Guide is an efficient addition product for the SAN environment, especially when users plan for the future. However, you must also carefully consider features and prices to ensure that you have purchased the best solution.