Storage Area Network Summary - IBM V7000 Introduction And Implementation Manual

The consequences of using Transparent Mode or a gateway device (IBM Flex System
FC3171 8Gb SAN Pass-thru) is that all FC traffic between compute nodes and IBM Flex
System V7000 Storage Node will be passed externally from the IBM Flex System Enterprise
Chassis to a FC switch on the external SAN fabric by the gateway device (or FCF for FCoE)
and back into the IBM Flex System Enterprise Chassis.

11.6 Storage Area Network summary

This chapter has reviewed each type of SAN connectivity between IBM Flex System V7000
Storage Node and compute nodes, detailing iSCSI over TCP/IP network, FCoE with 10 Gb
Ethernet, and FC. We have shown that each has capability to connect to an external SAN of
same type. The FCoE having the advantage of connecting to external FCoE or FC SAN in
FCF or NPV modes with the IBM Flex System Fabric CN4093 10Gb Converged Scalable
Switch.
The flexibility and use of Converged Network Adapter (CNA) on a compute node makes
FCoE and iSCSI attractive options with its use of 10 Gb Ethernet over a single network.
However, a number of sources recommend that FCoE should be separated from other
Ethernet traffic. This defeats the purpose of combining FC host bus adapter (HBA) and
Ethernet network interface card (NIC) in a CNA card.
FCoE is a relatively new storage protocol and is increasing in popularity with Ethernet speeds
to exceed that of FC. FCoE may well displace FC as the leading block based storage
protocol. Use of FCoE within the IBM Flex System Enterprise Chassis where only one FCF in
the internal dedicated network is employed, we would expect to see it perform at its optimum
(as with iSCSI and FC). In the Flex System environment, storage performance is critical, so
expectations of the selected storage protocol will be very high.
Within the IBM Flex System Enterprise Chassis, either option would be suitable between
storage and compute nodes. Note that iSCSI, FCoE, or FC each have their own attributes
and advantages over the others. Performance, for example, would be one attribute where
separation between the three could be measured, but this topic is beyond the scope of this
publication. Major determining factors in this choice of SAN include the external connectivity
whether FC or type of Ethernet. We would favor FCoE and FC over iSCSI in the enclosed IBM
Flex System Enterprise Chassis environment, as TCP/IP within the protocol layer is
unnecessary in this environment.
Regardless of which SAN storage protocol chosen, IBM Flex System V7000 Storage Node
adds flexibility and ease of management to Pure Flex, enhancing a solid foundation of
compute, storage, networking, and software resources.
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Chapter 11. SAN connections and configuration