Ha Pair Types And Requirements; Standard Ha Pairs - IBM N Series Hardware Manual

iSCSI direct-attached topologies
the storage controller. Direct-attached systems do not use networks or Ethernet switches.
iSCSI network-attached topologies
storage controllers through Ethernet switches. Networks can contain multiple Ethernet
switches in any configuration.
Mirrored HA pair configuration
that there are two copies, or
mirroring
Remote storage
location of the remote node.
Single storage controller configurations
controller is used. Single storage controller configurations have a single point of failure and
do not support cfmodes in Fibre Channel SAN configurations.
Standard HA pair configuration
automatically takes over for its partner when the partner node becomes impaired.

7.2 HA pair types and requirements

There are four types of HA pairs, each having distinct advantages and requirements:

Standard HA pairs

Mirrored HA pairs
Stretch MetroClusters
Fabric-attached MetroClusters
Each of these HA pair types is described in further detail in the following sections.
Tip: You must follow certain requirements and restrictions when setting up a new HA pair
configuration. These restrictions are described in further detail in the following sections.
7.2.1 Standard HA pairs
In a standard HA pair, Data ONTAP functions so that each node monitors the functioning of its
partner through a heartbeat signal sent between the nodes. Data from the NVRAM of one
node is mirrored by its partner. Each node can take over the partner's disks or array LUNs if
the partner fails. Also, the nodes synchronize time.
Standard HA pairs have the following characteristics:
Standard HA pairs provide high availability (HA) by pairing two controllers so that one can
serve data for the other in case of controller failure or other unexpected events.
Data ONTAP functions so that each node monitors the functioning of its partner through a
heartbeat signal sent between the nodes.
Data from the NVRAM of one node is mirrored by its partner. Each node can take over the
partner's disks or array LUNs if the partner fails.
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IBM System Storage N series Hardware Guide
are topologies in which the hosts are directly attached to
is similar to the standard HA pair configuration, except
plexes
.
refers to the storage that is accessible to the local node, but is at the
refers to a configuration set up so that one node
are topologies in which the hosts are attached to
, of the data. This configuration is also called
are topologies in which there is only one storage
data