Setup and Install

Planning the Fabric
TCP / IP
Chapter 2
26
the package to another node in the cluster, allowing services to remain available
with minimal interruption. MC/ServiceGuard via EMS, directly monitors cluster
nodes, LAN interfaces, and services (the individual processes within an application).
MC/ServiceGuard uses a heartbeat LAN to monitor the nodes in a cluster. It is not
possible to use HyperFabric as a heartbeat LAN. Instead a separate LAN must be
used for the heartbeat.
For more detailed information on configuring MC ServiceGuard, see “Configuring
HyperFabric with MC/ServiceGuard” on page 98 in this manual, as well as
Managing MC/ServiceGuard Part Number B3936-90065 March 2002 Edition.
• High Availability (HA): Supported
To create a highly available HyperFabric cluster, there cannot be any single point of
failure. Once the HP 9000 nodes and the HyperFabric hardware have been
configured with no single point of failure, MC/ServiceGuard and EMS can be
configured to monitor and fail-over nodes and services using ServiceGuard packages.
If any HyperFabric resource in a cluster fails (adapter card, cable or switch port), the
HyperFabric driver transparently routes traffic over other available HyperFabric
resources with no disruption of service.
The ability of the HyperFabric driver to transparently fail-over traffic reduces the
complexity of configuring highly available clusters with MC/ServiceGuard, because
MC/ServiceGuard only has to take care of node and service failover.
A “heartbeat” is used by MC/ServiceGuard to monitor the cluster. The HyperFabric
links cannot be used for the heartbeat. Instead an alternate LAN connection
(100BaseT, Ethernet, Token Ring, FDDI) must be made between the nodes for use as
a heartbeat link.
End To End HA: HyperFabric provides End to End HA on the entire cluster fabric at
the link level. If any of the available routes in the fabric fails, HyperFabric will
transparently redirect all the traffic to a functional route and, if configured, notify
MC/ServiceGuard or other enterprise management tools.
Active-Active HA: In configurations where there are multiple routes between nodes,
the HyperFabric software will use a hashing function to determine which particular
adapter/route to send messages through. This is done on a message-by-message
basis. All of the available HyperFabric resources in the fabric are used for
communication.
In contrast to Active-Passive HA, where one set of resources is not utilized until
another set fails, Active-Active HA provides the best return on investment because
all of the resources are utilized simultaneously. MC/ServiceGuard is not required for
Active-Active HA operation.
For more information on setting up HA HyperFabric clusters, see figure 2-3 “TCP/IP
High Availability Switched Configuration”.
• Dynamic Resource Utilization (DRU): Supported
When a new resource (node, adapter, cable or switch) is added to a cluster, a
HyperFabric subsystem will dynamically identify the added resource and start using
it. The same process takes place when a resource is removed from a cluster. The
difference between DRU and OLAR is that OLAR only applies to the addition or
replacement of adapter cards from nodes.