Welcome to the world of iSCSI, an essential component of modern data storage networking. In this article, we will delve into the basics of iSCSI, its functionality, and its significance in the realm of shared storage resources. Whether you are an IT professional seeking to expand your knowledge or a business owner exploring cost-effective storage solutions, understanding iSCSI is crucial.
So, what exactly is iSCSI? The acronym stands for Internet Small Computer System Interface. It is a transport layer protocol that enables the transmission of SCSI commands over TCP/IP networks. Developed by IBM in 1998 and standardized in 2003, iSCSI facilitates the establishment of shared-storage networks. With iSCSI, multiple servers and clients can effortlessly access central storage resources.
The functioning of iSCSI involves encapsulating SCSI commands within TCP/IP packets and transporting them between an initiator (server) and a target (storage device). This technology has gained immense popularity in small to midsize businesses, particularly in virtualized environments, where storage pools are accessible to all hosts within a cluster.
While iSCSI offers a cost-effective solution for storage networking, it is essential to acknowledge its performance limitations compared to the stalwart Fibre Channel. In the subsequent sections of this article, we will explore how iSCSI works, its various components, and the performance considerations associated with this versatile technology.
How iSCSI Works and its Components
iSCSI works by transporting block-level data between an iSCSI initiator (server) and an iSCSI target (storage device) over a TCP/IP network. The initiator sends SCSI commands encapsulated in TCP/IP packets, which are then disassembled by the target to be processed as if it was a locally connected SCSI device.
The main components of an iSCSI setup include:
- The iSCSI initiator: This can be software-based or a host bus adapter (HBA). Software initiators use standard Ethernet components, while HBAs offload processing from the server’s CPU to improve performance.
- The iSCSI target: This is the storage system hosting the storage resources.
iSCSI offers a cheaper and easier-to-manage alternative to Fibre Channel for connecting storage devices to servers. The use of standard Ethernet components makes it more cost-effective and simpler to adopt compared to specialized Fibre Channel equipment.
Comparison of iSCSI Components
| iSCSI Components | Description |
|---|---|
| iSCSI Initiator | Software-based or host bus adapter (HBA) |
| iSCSI Target | Storage system hosting storage resources |
By understanding how iSCSI works and its components, organizations can leverage this technology to create cost-effective and efficient storage networks.
iSCSI vs Fibre Channel and Performance Considerations
iSCSI was originally positioned as a more cost-effective alternative to Fibre Channel-based storage arrays, which offered higher performance but were more expensive and complex. However, advancements in iSCSI have narrowed the performance gap between the two technologies, especially with the adoption of SSDs.
Today, iSCSI is widely used in enterprise and cloud computing environments, providing performance that rivals or even exceeds that of Fibre Channel in similarly configured systems. The use of standard Ethernet makes iSCSI cheaper and easier to adopt compared to specialized Fibre Channel equipment.
To further enhance iSCSI performance, technologies such as multipathing, jumbo frames, and data center bridging can be implemented. These advancements allow iSCSI to achieve impressive speeds and efficiency, making it a highly attractive option for organizations in need of reliable and scalable storage solutions.
The increasing market success of iSCSI is evident in the acquisition of iSCSI storage array vendors by larger companies like Dell and Hewlett-Packard. This further validates the growing acceptance and adoption of iSCSI as a viable alternative to Fibre Channel, particularly when considering its improved performance capabilities and cost advantages.
FAQ
What is iSCSI?
iSCSI stands for Internet Small Computer System Interface. It is a transport layer protocol that allows SCSI commands to be sent over TCP/IP networks.
When was iSCSI developed?
iSCSI was developed by IBM in 1998 and ratified as a standard in 2003.
How does iSCSI work?
iSCSI works by encapsulating SCSI commands in TCP/IP packets and transporting them between an initiator (server) and a target (storage device) over a TCP/IP network.
What are the main components of an iSCSI setup?
The main components of an iSCSI setup include the iSCSI initiator (server) and the iSCSI target (storage device).
What are the differences between iSCSI and Fibre Channel?
iSCSI is a cost-effective solution for storage networking, while Fibre Channel offers higher performance. iSCSI uses standard Ethernet components, making it cheaper and easier to adopt compared to specialized Fibre Channel equipment.
Can iSCSI match the performance of Fibre Channel?
Advancements in iSCSI, especially with the adoption of SSDs, have narrowed the performance gap between iSCSI and Fibre Channel. iSCSI now offers performance that rivals or even exceeds that of Fibre Channel in similarly configured systems.