Understanding and Designing Serviceguard Disaster Recovery Architectures

M
M by N A type of Symmetrix grouping in which up to two Symmetrix frames may be configured on either
side of a data replication link in a Metrocluster with EMC SRDF configuration. M by N
configurations include 1 by 2, 2 by 1, and 2 by 2.
manual failover Failover requiring human intervention to start an application or service on another node.
Metrocluster A Hewlett-Packard product that allows a customer to configure an Serviceguard cluster as a
disaster recovery metropolitan cluster.
metropolitan
cluster
A cluster that is geographically dispersed within the confines of a metropolitan area requiring
right-of-way to lay cable for redundant network and data replication components.
mirrored data Data that is copied using mirroring.
mirroring Disk mirroring hardware or software, such as MirrorDisk/UX. Some mirroring methods may allow
splitting and merging.
mission critical
application
Hardware, software, processes, and support services that must meet the uptime requirements of
an organization. Examples of mission critical application that must be able to survive regional
disasters include financial trading services, e-business operations, 911 phone service, and patient
record databases.
mission critical
solution
The architecture and processes that provide the required uptime for mission critical applications.
multiple points of
failure (MPOF)
More than one point of failure that can bring down a Serviceguard cluster.
multiple system
high availability
Cluster technology and architecture that increases the level of availability by grouping systems
into a cooperative failover design.
mutual recovery
configuration
A continental cluster configuration in which each cluster serves the roles of primary and recovery
cluster for different recovery groups. Also known as a bi-directional configuration.
N
network failover The ability to restore a network connection after a failure in network hardware when there are
redundant network links to the same IP subnet.
notification A message that is sent following a cluster or package event.
NPIV (N_Port ID
Virtualization)
A virtual FC port(VFC) is created over the physical FC port (PFC) on the host and presented over
to the guest. There is a WWN associated with the VFC, which can be used to provision storage
exclusively for the guest. Through the VFC, the guest will have direct visibility to the SAN to which
the PFC is connected. The WWN associated with the VFC shows up on the storage array
configuration tool and LUNs can be provisioned as how it is done for PFC.
O
offline data
replication.
Data replication by storing data offline, usually a backup tape or disk stored in a safe location;
this method is best for applications that can accept a 24-hour recovery time.
online data
replication
Data replication by copying to another location that is immediately accessible. Online data
replication is usually done by transmitting data over a link in real time or with a slight delay to
a remote site; this method is best for applications requiring quick recovery (within a few hours
or minutes).
P
package alert Time at which a message is sent indicating a problem with a package.
package event A package condition such as a failure that causes a notification message to be sent. Package
events can be accompanied by alerts, but not alarms. Messages are for information only; the
cmrecovercl command is not enabled for a package event.
package recovery
group
A set of one or more packages with a mapping between their instances on the Primary Cluster
and their instances on the Recovery Cluster.
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