Compaq Parallel Database Cluster Model PDC/O2000 for Oracle8i and Windows 2000 Administrator Guide

Cluster Architecture 2-49
Table 2-6
Features of Active/Standby and Active/Active Configurations for Redundant Fibre Channel
Arbitrated Loops
continued
I/O Path Configuration Advantage Disadvantage
Active/active with two or more
RA4000/RA4100 Arrays
Provides a small but measurable
improvement in I/O performance
over the active/standby
configuration because both Fibre
Host Adapters in each node and
both Storage Hubs or FC-AL
Switches are simultaneously
active. This improvement can be
meaningful for customers with
large cluster databases or high
I/O transaction requirements.
Provides better load balancing
between the two Storage Hubs
than the active/standby
configuration. Both Storage
Hubs or FC-AL Switches are
connected to the same or
equivalent numbers of both
active and standby array
controllers in the
RA4000/RA4100 Arrays.
Does not provide true cabling
symmetry between Storage
Hubs or FC-AL Switches and
array controllers if you
consistently configure the top or
rightmost array controller as the
active controller. Each Storage
Hub or FC-AL Switch is cabled
to top (active) array controllers
in some RA4000/RA4100 Arrays
and bottom (standby) controllers
in others. You can achieve
cabling symmetry if you
configure the bottom array
controller in some
RA4000/RA4100 Arrays as
active. However, this requires
using Secure Path to configure
the lower array controller as
active if it is in standby mode.