high availability | A combination of technology, processes, and support partnerships that provide greater application |
| or system availability. |
J, K, L |
|
local cluster | A cluster located in a single data center. This type of cluster is not disaster tolerant. |
local failover | Failover on the same node; this most often applied to hardware failover, for example local LAN |
| failover is switching to the secondary LAN card on the same node after the primary LAN card |
| has failed. |
logical data | A type of |
replication | filesystem or the database. Complex transactions may result in the modification of many diverse |
| physical blocks on the disk. |
LUN | (Logical Unit Number) A SCSI term that refers to a logical disk device composed of one or more |
| physical disk mechanisms, typically configured into a RAID level. |
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. |
Maintenance mode | A recovery group is in the maintenance mode when it is disabled. The cmrecovercl |
| |
| command moved the recovery group out of the maintenance mode. When a recovery group is |
| in the maintenance mode, recovery is not allowed. |
manual failover | Failover requiring human intervention to start an application or service on another node. |
Metrocluster | A |
| disaster tolerant metropolitan cluster. |
Metrocluster | Metrocluster uses a configuration file that includes variables that define the environment for the |
Environment File | Metrocluster to operate in a Serviceguard cluster. This configuration file is referred to as the |
| Metrocluster environment file. This file needs to be available on all nodes in the cluster for |
| Metrocluster to function successfully. |
metropolitan | A cluster that is geographically dispersed within the confines of a metropolitan area requiring |
cluster | |
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 | Hardware, software, processes and support services that must meet the uptime requirements of |
application | an organization. Examples of mission critical application that must be able to survive regional |
| disasters include financial trading services, |
| record databases. |
mission critical | The architecture and processes that provide the required uptime for mission critical applications. |
solution |
|
multiple points of | More than one point of failure that can bring down an Serviceguard cluster. |
failure (MPOF) |
|
multiple system | Cluster technology and architecture that increases the level of availability by grouping systems |
high availability | into a cooperative failover design. |
mutual recovery | Continentalclusters configuration in which each cluster serves the roles of primary and recovery |
configuration | cluster for different recovery groups. Also known as a |
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. |
518 Glossary