Waiting for the bus to deliver datacentre-class PC servers

Users will be able to migrate to 64-bit Intel server technology delivering the potential for data centre-class PC servers by the...

Users will be able to migrate to 64-bit Intel server technology delivering the potential for data centre-class PC servers by the end of the year, writes Cliff Saran.

However, when 64-bit Itanium servers start shipping, PC manufacturers will have to use existing PCI bus technology that will hinder performance. The technology required to bring genuine mainframe-class performance and reliability on 64-bit PC servers is still two to three years away.

The bus provides a means for peripheral devices to communicate with the processor but the architecture of the PCI bus was not designed for scalability or reliability.

The PCI bus has extremely poor fault tolerance. It allows only one device at a time to transmit data and a faulty PCI card can effectively block the bus, preventing the PC from functioning correctly.

The next generation of PC architecture is Infiniband, an emerging standard that brings together two industry initiatives - Next Generation I/OP (Ngio) and PCI-X.

Instead of being based on a bus, Infiniband is a switched fabric that uses the kind of technology found in high-end computers. The switch is analogous to a network switch. In effect each peripheral has its connection or bus, so no single device can stop the computer from functioning.

According to Intel, the I/O fabric is designed to scale without encountering the bottlenecks that bus architectures experience as workload on the server increases.

Another benefit of this new architecture is what Intel describes as the physical modularity of Infiniband technology. This means that users will no longer need to buy excess capacity (ie more powerful servers) up-front in anticipation of future growth. Instead, they will be able to buy what they need at the outset and "pay as they grow" to add capacity without affecting operations or installed systems.

Intel says Infiniband will initially be used to connect servers with remote storage and networking devices and other servers. It will also be used inside servers for inter-processor communication in parallel clusters.

The technology promises greater performance, easier and faster sharing of data, built-in security and quality of service, and improved usability. Intel also says Infiniband will make it far easier to add, remove or upgrade servers than is the case with today's shared-bus I/O cards.

Intel says the Infiniband architecture has been designed to reduce the total cost of ownership by focusing on datacentre reliability and scalability.

The technology addresses reliability by creating multiple redundant paths between nodes, thus reducing the amount of hardware that needs to be purchased. It also moves from the load-and-store-based communications methods used by shared local bus I/Os to a more reliable message passing approach.

Benefits of Infiniband

  • Next generation PC bus architecture

  • Based on high-end architecture

  • Ability to scale as workload on the server increases

  • Users will be able to pay for server capacity pay as they grow

  • Infiniband can be used to connect servers to remote storage

  • Reduces total cost of ownership

  • Creates multiple redundant paths for improved reliability

  • Easier to add, remove or upgrade servers

  • More reliable message passing approach

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