How do you choose between a fibre channel SAN and an iSCSI SAN?

1 FC SAN basics

FC is a high-speed, low-latency protocol that uses optical cables and switches to connect storage devices and servers. FC can operate at speeds of up to 128 Gbps, and supports multiple topologies, such as point-to-point, arbitrated loop, and switched fabric. FC SANs are ideal for applications that require high performance, availability, and scalability, such as database, virtualization, and backup. However, FC SANs also have some drawbacks, such as higher cost, complexity, and maintenance. You need to invest in specialized hardware, software, and skills to set up and manage a FC SAN.

2 iSCSI SAN basics

iSCSI is a protocol that uses the TCP/IP stack to transport SCSI commands over Ethernet networks. iSCSI can run on existing network infrastructure, and can use standard Ethernet switches, routers, and cables. iSCSI SANs are easier to deploy, configure, and troubleshoot than FC SANs, and are more cost-effective and flexible. iSCSI SANs can also leverage the benefits of IP networking, such as security, routing, and convergence. However, iSCSI SANs also have some limitations, such as lower speed, higher latency, and more overhead. iSCSI SANs are more suitable for applications that are not very sensitive to performance or reliability, such as file sharing, email, and web hosting.

3 How to compare FC and iSCSI SANs

When deciding between FC and iSCSI SANs, you must consider factors such as budget, existing infrastructure, performance requirements, availability needs, and scalability goals. Ask yourself questions such as how much you can afford to spend on your SAN. Do you have a robust and reliable Ethernet network? How fast do you need your data? How available do you need your data? And how scalable do you need your SAN? FC SANs are more expensive and offer higher speed and lower latency than iSCSI SANs. However, iSCSI SANs can benefit from faster Ethernet speeds, quality of service (QoS), jumbo frames, network redundancy, load balancing, and clustering for improved performance and availability. FC SANs provide higher availability and fault tolerance with multipathing, redundancy, and failover. iSCSI SANs rely on the underlying IP network for availability. FC SANs can scale up to thousands of devices with optical cables and switches while iSCSI SANs can scale up to hundreds of devices with Ethernet cables and switches. However, iSCSI SANs can be enhanced with virtualization, cloud, and software-defined storage.