Comparison Of Ha Pair Types - IBM N Series Hardware Manual

7.1.4 Comparison of HA pair types

Table 7-1 identifies the types of N series HA pair configurations (or High Availability pairs) and
where each might be applied.
Table 7-1 Configuration types
HA pair If A-SIS
configuration active
type
Standard HA pair No
configuration
Mirrored HA pair Yes
configuration
Stretch Yes
MetroCluster
Fabric-attached Yes
MetroCluster
a. SAS configurations are limited to 5 meters between nodes
Certain terms have particular meanings when used to refer to HA pair configuration. The
specialized meanings of these terms are as follows:
An HA pair configuration
other if one of the two systems becomes impaired. In Data ONTAP documentation and
other information resources, HA pair configurations are sometimes also called
When in an HA pair configuration, systems are often called
called the
Controller failover
enables two storage systems to take over each other's data. This configuration improves
data availability.
FC direct-attached topologies
the storage system. Direct-attached systems do not use a fabric or Fibre Channel
switches.
FC dual fabric topologies
independent fabrics that are connected to storage systems. Each independent fabric can
consist of multiple Fibre Channel switches. A fabric that is zoned into two logically
independent fabrics is not a dual fabric connection.
FC single fabric topologies
systems through a single Fibre Channel fabric. The fabric can consist of multiple Fibre
Channel switches.
Distance between
nodes
a
Up to 500 meters
a
Up to 500 meters
Up to 500 meters
(270 meters if Fibre
Channel speed 4 Gbps
and 150 meters if Fibre
Channel speed is 8
Gbps)
Up to 100 km depending
on switch configuration.
For gateway systems, up
to 30 km.
is a pair of storage systems configured to serve data for each
local node
, and the other node is called the
cluster failover
, also called
are topologies in which the hosts are directly attached to
are topologies in which each host is attached to two physically
are topologies in which the hosts are attached to the storage
Failover possible Notes
after loss of entire
node (including
storage)
No Use this configuration to provide
higher availability by protecting
against many hardware single
points of failure.
No Use this configuration to add
increased data protection to the
benefits of a standard HA pair
configuration.
Yes Use this configuration to provide
data and hardware duplication
to protect against a local
disaster.
Yes Use this configuration to provide
data and hardware duplication
to protect against a larger-scale
disaster.
nodes
partner node
(CFO), refers to the technology that
Chapter 7. Highly Available controller pairs
HA pairs
.
. One node is sometimes
remote node
or .
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