Article: ISCSI Enables High Performance Block Storage at Low Cost

The way iSCSCI works is by transporting block-level data between an iSCSI initiator on a server and an iSCSI target on a storage device.

• By Mensah Alkebu-Lan
• 29 May 2023

This is my @VMware home lab setup. It's been disassembled for over 6 months now since moving. Need to get it back online 😑

4x Dell T5810s with:
Intel Xeon E5-2680v3 (12 core, 24 threads)
128GB DDR4 ECC each
Intel X520 10Gbps cards
Custom @TrueNAS iSCSI storage box pic.twitter.com/r9ZeBc2Eul

— vswitchzero (Mike) (@vswitchzero) March 3, 2022

Table of Contents

• Overview
• References
  

Overview

Internet small computer system interface (ISCSI) can be used to create a storage area network (SAN). It enables high performance block storage at low cost. The way iSCSCI works is by transporting block-level data between an iSCSI initiator on a server and an iSCSI target on a storage device.

An iSCSI initiator is a piece of software or hardware installed on a server to send data to and from an iSCSI-based storage array or iSCSI target. An iSCSI target is a server that hosts the storage resources and allows access to the storage via one or more NICs, HBAs, or iSOEs.

The iSCSI protocol encapsulates SCSI commands and assembles the data in packets for the TCP/IP layer. Upon the arrival of these data packets, the iSCSI protocol disassembles these packets, separating the SCSCI commands so the operating system will see the storage as if it was a locally connected SCSI device.

An iSCSI target is a device that responds to iSCSI commands. An iSCSI device can be an end node such as a storage device, or it can be an intermediate device such as a bridge between IP and fibre channel (FC) devices. Configuring iSCSI storage is similar to setting up FC storage, with the creation of logical unit numbers the basis of the process. To transport SCSI commands over the IP network, an iSCSI driver must be installed on the iSCSI host and target.

Below is an example of an iSCSI host that connects to the system over an Ethernet network by transmitting SCSI over TCP/IP:

Contact us for more information about our iSCSI-based storage consulting services.

References

1. “iSCSI overview.” IBM. Accessed 19 April 2023.
2. “What is iSCSI?” SNIA. Accessed 20 April 2023.
3. Raffo, Dave. “What is iSCSI and How Does it Work?” TechTarget. Accessed 20 April 2023.