Fibre Channel is spelled as Fibre Channel, andSCSI interfaceSimilarly, Fibre Channel is not an interface technology originally designed for hard disks, but is designed specifically for network systemsstorage system The demand for speed is gradually applied to hard disk systems.Fibre Channel hard drives are designed to improveHard disk storageThe speed and flexibility of the system have been developed. Its appearance has greatly improved the communication speed of multi hard disk systems.The main features of Fibre Channel are:Hot plugPerformance, high-speed bandwidth, remote connection, large number of connecting devices, etc.
Fibre Channel is designed for multi hard disk system environments such as servers, which can meet the requirements of high-end workstations, servers, mass storage subnetworks, and peripheralsHub, switches, andPoint to pointConnection is bidirectional and serialData communicationEqual system alignmentData transmission rateRequirements.
Fibre Channel can use coaxial cable andlight-guide fiberAs the connection equipment, most of them use optical fiber media, while the traditional copper shaft cables such asTwisted pairCan be used for small-scale network connection deployment.However, Fibre Channel with coaxial cable has the same old problems as copper media, such as short transmission distance (30 meters, depending on the specific cable) and susceptibility to electromagnetic interference (EMI).
Although copper media is also suitable for some environments, optical cables are the best choice for large-scale storage networks deployed using Fibre Channel.Optical cables are classified according to their diameter and "mode", and the diameter is measured in microns.There are two cable modes: single-mode is to transmit a single signal at a time, while multimode can transmit multiple signals by continuously reflecting signals on the glass core wall of the optical cable.The recognized standards and grades of optical fiber channel are: diameter 62.5micronMultimode optical cable175 m, 50 μ m diameter multimode optical cable 500 m, and 9 μ m diameterSingle mode optical cable10km.
Optical fiber can now provide 100MBps of actual bandwidth, while its theoretical limit is 1.06GBps.However, some companies have begun to launch 2.12Gbps products, which support the next generation of Fibre Channel (i.e. Fibre Channel II).However, in order to obtain higher data transmission rate, fiber products in the market sometimes use multiple Fibre Channel to achieve higher bandwidth.
Detailed introduction
Fibre Channel is a very different interface from SCSI or IDE. It is very similar to the conversion start of Ethernet.It was originally designed for the network, but laterstorageThe demand for high bandwidth is slowly migrated to the currentstorage system Come up.Fibre Channel is usually used to connect a SCSI RAID (or some other commonly used RAID types) to meet high-end work or server pair heightData transmission rateRequirements.
Fibre Channel provides point-to-point, converted loop interfaces.It is used to communicate with SCSIInternet Protocol(IP) is designed to work together with other protocols, but it has also been criticized for its lack of compatibility, mainly because (just like the early small computer system interface technology) manufacturers sometimes interpret the specifications differently and implement them differently.[1]
Advantages and disadvantages
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advantage
There are many connected devices, up to 126 devices can be connected
Low CPU usage
supportHot plug, onHost systemFibre Channel hard drives can be installed or removed at runtime
Optical fiber and copper cable can be connected
High bandwidth. Under the appropriate environment, Fibre Channel is the fastest of the existing products.
Strong versatility
Large connection distance, far beyond other similar products
shortcoming
The product is expensive
Complex organization
Channel partition
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Conceptually, Fibre Channel partition ratioVirtual LANIt is more consistent with the concept of partition.At first glance, Fibre Channel zoning seems more complex, but what hides behind the complexity is actually simple.A device node, or global name (WWN), can exist in multiple different partitions at the same time.This ability can really be abused!A sound and manageable partition setting requires a certain architecture -- it can't be solved in a minute.
There are two types of partitions: soft partitions and hard partitions.
Soft partition
Soft zoning means that the switch places the device's global name in one zone, regardless of which port is connected.For example, if global name Q and global name Z are in the same partition, they can talk to each other.Similarly, if Z and A are in another partition, Z and A can see each other, but A cannot see Q. This is the complexity of the partition;This characteristicEthernet switch Not common in.
Hard partition
Hard partitions are more similar to those in the Ethernet worldVirtual LAN。If a port is placed in a partition, any traffic connected to the port will come from the partition or the partitions set.Of course, if someone can move the optical cable, this partition will be less secure in the face of physical attacks.But do you need to worry about this situation?Therefore, the best setting for SAN is: switch hard zoning, and access to array side (target)Logical unit number(LUN).YourStorage arrayGlobal name masking is also required so that multiple initiators can be partitioned to see the array side at the same time.[2]
