SAN is extremely durable and fast due to low data transfer latencies and a focus on guaranteed data block delivery. These blocks are a portion of binary data allocated onto the storage.
In the case of a USB drive, it is a simple data block. SAN, in turn, contains data blocks of different volumes distributed between hard drives. As the network is developed for high-loaded storage devices, it uses a strong cyclic redundancy check CRC — a hash function used to produce a checksum in order to detect errors in data. Fibre channel is more isolated, as compared with TCP-IP based networks, thus minimizing security issues, malware aftermaths and human errors.
To avoid purchasing special hardware, you can opt for an Ethernet-based network. It allows the same block-level storage access but uses conventional Ethernet networks. It is also worth noting here that the development of FC SANs made it feasible for manufacturers to design large devices with many hard drives, generally referred to as "storage arrays". These typically use a data protection method such as RAID Redundant Array of Inexpensive Disks , which can combine groups of physical hard drives into arrays, with either multiple copies of data or a calculated parity that enables reconstruction of data.
If a hard drive fails which is usually inevitable with spinning disks , it can simply be removed and replaced, and the data is rebuilt on the drive. Thus the space can be used much more efficiently and dynamically.
The overall result of using an FC SAN is a system that is very reliable, very fault tolerant, and very expensive. Server HBA cards are costly, FC Switches and Storage Arrays are quite expensive, and even the fiber optic cables connecting all this together are not cheap.
The capabilities and limitations of this technology are different from those of an FC SAN in several ways. This is basically the building block that most of the Internet as we know it is built on. The first obvious advantage to iSCSI is that most servers are already connected to an Ethernet network and have at least one IP address.
The second is that there is no need to purchase expensive FC hardware and run a second set of fiber optic cables. Another advantage to this method is that there is no need to learn Fibre Channel skills; a company that has an Ethernet network is likely to already have personnel with networking knowledge, and iSCSI is relatively easy to set up.
Ethernet does not guarantee "in order" frame delivery, which causes TCP to detect when packets are lost or dropped and retransmit them. Another disadvantage is redundancy: FC SANs are typically built with multiple HBAs on the servers, dual isolated Fabrics, and multiple target ports on the storage arrays. However, Xerox permitted the specification to be made public, and it was approved as a standard in by the Institute of Electrical and Electronics Engineers IEEE Since then, Ethernet has become ubiquitous in offices, data centers, and even most homes.
Speeds have increased from 3 Mbps to a whopping Gbps and higher. Basically it allows the encapsulation of native Fibre Channel packets into Ethernet frames. FCoE does require some enhancements to the Ethernet network, but most if not all modern Data Center Ethernet switches support this.
The advantages of FCoE over pure FC are primarily in reduced cost, no need to buy dedicated FC hardware, and not as many advanced skills needed to install and manage it. The disadvantages are that with FCoE, storage traffic is being sent over the same network as other traffic, and contention is possible, and that only some storage arrays support native FCoE.
The advantages of FCoE over iSCSI are mainly performance and reliability, however with a very fast Ethernet network in both cases, the difference may only show up in very data-intensive situations. The disadvantage depending on one's point of view are that FCoE still requires some FC skills, and some enhanced hardware. So how can we decide which is best? This is compounded by the presence of storage equipment that does not support a protocol other than FC.
Looking ahead, however, eventually most of the components of an FC SAN will approach the end of its useful life and need to be replaced. In many cases, a fast, modern Ethernet network is already in place, and servers will already have Ethernet interfaces, possibly even already equipped with CNAs. If the purchase of storage equipment capable of supporting those protocols or "hybrid" switches that can bridge between FC storage and Ethernet networks is a possibility, this vision could become a reality.
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Free Software Development Course. Login details for this Free course will be emailed to you. Email ID. Contact No. It runs on the dedicated infrastructure which is separate from the user and server. It runs on the same enterprise application which is deployed in the user network. It is too expensive because of the dedicated infrastructure in the storage area network.
It is a complex technique and labour intensive. Skill labour is required to manage the fibre channels.
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