FW 05.01.00 and SW 07.01.00 HP StorageWorks SAN High Availability Planning Guide (AA-RS2DC-TE, June 2003)

Introduction to HP Fibre Channel Products
19SAN High Availability Planning Guide
Director Performance
Directors provide the following general performance features:
■ High bandwidth — Each port provides full-duplex serial data transfer at a
rate of 2.125 Gbps.
■ High availability — To ensure an availability of 99.999%, director design
provides a redundant configuration of critical components with automatic
failure detection and notification.
Pairs of critical FRUs (logic cards, power supplies, and cooling fans) provide
redundancy in case of failure. When an active FRU fails, the backup FRU
takes over operation automatically (failover) to maintain director and Fibre
Channel link operation. High availability is also provided through concurrent
firmware upgrades and spare or unused Fibre Channel ports.
■ Low latency — The latency is less than 2.5 microseconds between
transmission of a frame at a source port to receipt of the frame at the
corresponding destination port (with no port contention).
■ Local control — Actions taking place at a device N_Port seldom affect
operation of other ports; therefore, servers need to maintain little or no
information about other connected devices in a SAN.
■ Low communication overhead — Fibre Channel protocol provides efficient
use of transmission bandwidth, reduces interlocked handshakes across the
communication interface, and efficiently implements low-level error recovery
mechanisms. This results in little communication overhead in the protocol and
a director bit error rate (BER) less than one bit error per trillion (10
12
) bits.