Building Disaster Recovery Serviceguard Solutions Using Metrocluster with 3PAR Remote Copy for Linux B.01.00.00, July 2013

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, N
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.
notification A message that is sent following a cluster or package event.
O, P
physical data
replication
An on-line data replication method that duplicates I/O writes to another disk on a physical block
basis. Physical replication can be hardware-based where data is replicated between disks over
a dedicated link (For example, EMC’s Symmetrix Remote Data Facility, the HP StorageWorks E
Disk Array XP Series Continuous Access, 3PAR Remote Copy and EVA Continuous Access), or
software-based where data is replicated on multiple disks using dedicated software on the primary
node (For Example, MirrorDisk/UX).
Q
quorum server A cluster node that acts as a tie-breaker in a disaster tolerant architecture in case all of the nodes
in a data center go down at the same time. See also arbitrator.
R, S
Recovery Cluster A cluster on which recovery of a package takes place following a failure on the cluster.
resynchronization The process of making the data between two sites consistent and current once systems are restored
following a failure. Also called data resynchronization.
rolling disaster A second disaster that occurs before recovering from a previous disaster, For Example, while
data is being synchronized between two data centers after a disaster, one of the data centers
fails, interrupting the data synchronization process. Rolling disasters may result in data corruption
that requires a reload from tape backups.
sub-clusters Sub-clusters are clusterwares that run above the Serviceguard cluster and comprise only the nodes
in a Metrocluster site. Sub-clusters have access only to the storage arrays within a site.
T-Z
volume group In LVM, a set of physical volumes such that logical volumes can be defined within the volume
group for user access. A volume group can be activated by only one node at a time. Serviceguard
can activate a volume group when it starts a package. A given disk can belong to only one
volume group. A logical volume can belong to only one volume group.
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