Справочник Пользователя для IBM Flex System V7000 Expansion Enclosure 4939H29

Draft Document for Review January 29, 2013 12:52 pm

IBM Flex System V7000 Storage Node Introduction and Implementation Guide

Storage Area Network (SAN) has long been regarded as consisting of dedicated equipment 
which connects host servers to share remote storage. This has enabled storage of varying 
size and performance to be used and allocated more efficiently and help eliminating islands of 
storage. Multiple servers of differing platform types can benefit from a single new storage 
controller and its associated attributes such as performance or provisioning technologies. 
With the increased efficiencies and economies this has brought, organizations have been well 
prepared for the storage capacity increase and demand experienced in recent years. The 
most common and reliable protocol used in today’s SAN has been Fibre Channel (FC).

Fibre Channel SANs are generally regarded as the high-performance approach to storage 
networking. With a Fibre Channel SAN, storage arrays are equipped with FC ports that 
connect to FC switches. Similarly, servers are equipped with Fibre Channel host bus adapters 
(HBAs) that also connect to Fibre Channel switches. Therefore, the Fibre Channel SAN fabric 
which is the set of FC switches, are a separate and exclusive network for storage traffic. FC 
offers relatively high-speed, low-latency, and back-pressure mechanisms that provide 
lossless behavior. It is designed not to drop data packets during periods of network 
congestion.

The speeds offered from FC has until recently always been faster than that of Ethernet where 
FC used speeds of 2 Gbps, 4 Gbps, 8 Gbps and more recently16 Gbps, Ethernet has offered 
100 Mbps or 1 Gbps. But with improved and faster Ethernet communications to a host server 10 
Gbps is becoming more widely available and used for host server connections. Higher speeds 
of 40-Gbps Ethernet are becoming available, and a 100-Gbps Ethernet will soon arrive. With 
newer ‘lossless’ Ethernet networks also, from a simple data transmission speed perspective, 
Ethernet can now meet or exceed the speeds that are available by using FC.

With these increased Ethernet transmission speeds becoming available there is a growing 
interest in convergence where FC and traditional Ethernet data traffic can be merged and 
transferred over a single medium. Another driving factor for convergence is improved asset 
utilization and cost of ownership, similar to the convergence of voice and data networks that 
has occurred. By using a single infrastructure for multiple types of network traffic, the costs of 
procuring, installing, managing, and operating the data center infrastructure can be lowered. 
Where multiple types of adapters, switches, and cables were once utilized for separate 
networks, a single set of infrastructure will take its place, providing savings in equipment, 
cabling, and power requirements. The improved speeds and capabilities of a lossless 
10-Gbps Ethernet offer the hope of a converged environment. 

This section looks at how the IBM Flex System V7000 Storage Node is able to utilise 
convergence technologies in order to communicate with the compute nodes and external 
storage equipment. We look at the three type of SANs offered within the IBM Flex System 
Enterprise Chassis iSCSI, FCoE and FC. 

For in depth details of FCoE and iSCSI including protocols which can use the high speed 
Ethernet networks and recommendations see Storage and Network Convergence Using 
FCoE and iSCSI, SG24-7986. For in depth details of FC see Introduction to Storage Area 
Networks and System Networking, SG24-5470.

The IBM Flex System V7000 Storage Node uses 10Gb Ethernet adapter for iSCSI and FCoE 
communications plus optional fibre channel (FC) adapters for FC connectivity to the compute