Hello, everyone!
What are the basic concepts of storage protocols? In this post, we systematically describe some basic concepts of storage.
SCSI
Small Computer System Interface (SCSI) is the most common method for connecting storage devices to servers. SCSI was first developed in 1979 and is an interface technology for mid-range computers. With the development of computer technologies, SCSI is now completely transplanted to ordinary PCs. SCSI-3 is the basis of all storage protocols, because all storage protocols use the SCSI instruction set.
iSCSI
Internet Small Computer System Interface (iSCSI) is an Internet Protocol (IP)-based storage networking standard for linking data storage facilities. It provides block-level access to storage devices by carrying SCSI commands over a TCP/IP network. Used over the IP-based SAN, the iSCSI protocol provides quick, cost-effective, and long-distance storage solutions. iSCSI encapsulates SCSI commands into a TCP or IP packet, enabling I/O data blocks to be transferred over the IP network.
Fibre Channel
Fibre Channel is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to servers in storage area networks (SAN) in commercial data centers. Fibre Channel networks form a switched fabric because the switches in a network operate in unison as one big switch. Fibre Channel typically runs on optical fiber cables within and between data centers, but can also run on copper cabling. Fibre Channel is a high-performance serial connection standard. The interface transmission rate can be 16 Gbit/s or 32 Gbit/s. The transmission media can be copper cables or optical fibers. The transmission distance is long and multiple interconnection topologies are supported.
SAS
Serial Attached SCSI (SAS) is the serial standard of the SCSI bus protocol. SAS uses the serial technology to achieve higher transmission rate and better scalability, and is compatible with SATA disks. The transmission rate of the SAS reaches 6 Gbit/s and 12 Gbit/s, and the SAS supports the full-duplex mode.
NVMe
1. NVMe is a controller interface standard developed for enterprises and client systems that use PCIe SSDs.
2. It is not only a logical protocol interface, but also an instruction standard and a specified protocol.
3. NVMe covers optimized controller register interfaces, command sets, and I/O queue management.
4. NVMe features low latency, high IOPS, and low power consumption.
That's all for now. More basic knowledge about storage will be introduced later.
