Configuring Citrix MetaFrame for Windows 2000 Terminal Services

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There are two flavors of RAID controllers. Hardware RAID relies on special functionality built into the hard disk control. This is usually done with server-class machines, and can come in all shapes and sizes. Some devices allow administrators to hot-swap a failed device, plugging the new drive in without having to take the server down. The information is then automatically rebuilt on the new drive. Hardware RAID is most commonly done with Small Computer System Interface (SCSI) drives, because they usually spin much faster and provide better throughput than their Integrated Drive Electronics (IDE) counterparts. The second type of RAID is a software-controlled solution. This is typically much slower than a hardware RAID controller, and usually is used when a hardware RAID solution cannot be afforded. Software RAID erases many of the performance gains that hardware RAID provides, and is best used only when fault tolerance is a must and software RAID is the only way to achieve it.

Fibre Channel

Fibre Channel is a special transmission technology that is designed to provide extremely fast communications between storage and communications networks. With Fibre Channel, hosts can communicate with a storage

system (via SCSI) and each other (over Internet Protocol, or IP) using the same network. Despite its name, Fibre Channel is designed to work over fibre, coaxial, or twisted-pair cabling. Each port with Fibre Channel uses two cables to transmit and receive data. A transmitter (TX) is connected to a receiver (RX) at the other end. The connection can be connection-oriented or connectionless using switched technology. In connection-oriented Fibre Channel, an arbitrary loop can contain 127 nodes. Nodes can be either a storage system or another computer. The biggest use of Fibre Channel technology is in Storage Area Networks (SANs), which we will discuss next. Figure 2.1 shows an example of Fibre Channel in both switched and loop environments.

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