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I/O Consolidation in the Data Center

Chapter Description

This chapter explains the benefits and challenges of designing physical infrastructure to simultaneously carry multiple types of traffic.

Why I/O Consolidation Has Not Yet Been Successful

There have been previous attempts to implement I/O consolidation. Fibre Channel itself was proposed as an I/O consolidation network, but its poor support for multicast/broadcast traffic never made it credible.

Infiniband has also attempted I/O consolidation with some success in the HPC world. It has not penetrated a larger market due to its lack of compatibility with Ethernet (again, no good multicast/broadcast support) and with FC (it uses a storage protocol that is different from FC) and to the need of gateways that are bottlenecks and incompatibility points.

iSCSI has been probably the most significant attempt at I/O consolidation. Up to now it has been limited to the low performance servers, mainly because Ethernet had a maximum speed of 1 Gbit/s. This limitation has been removed by 10 Gigabit Ethernet (10GE), but there are concerns that the TCP termination required by iSCSI is onerous at the 10Gbit/s speed. The real downside is that iSCSI is "SCSI over TCP," it is not "FC over TCP," and therefore it does not preserve the management and deployment model of FC. It still requires gateways, and it has a different naming scheme (perhaps a better one, but anyhow different), a different way of doing zoning, and so on.

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