Security Solutions

package recovery
group
A set of one or more packages with a mapping between their instances on the cluster and their
instances on the Recovery Cluster.
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 or the HP StorageWorks
E Disk Array XP Series Continuous Access), or software-based where data is replicated on multiple
disks using dedicated software on the primary node (For Example, MirrorDisk/UX).
planned downtime An anticipated period of time when nodes are brought down for hardware maintenance, software
maintenance (OS and application), backup, reorganization, upgrades (software or hardware),
etc.
primary package The package that normally runs on the cluster in a production environment.
PVOL A primary volume configured in an P9000 and XP series disk array that uses Continuous Access.
PVOLs are the primary copies in physical data replication with Continuos Access on the P9000
and XP.
Q
quorum See See cluster quorum..
quorum server A cluster node that acts as a tie-breaker in a disaster recovery architecture in case all of the nodes
in a data center go down at the same time. See also arbitrator.
R
R1 The Symmetrix term indicating the data copy that is the primary copy.
R2 The Symmetrix term indicating the remote data copy that is the secondary copy. It is normally
read-only by the nodes at the remote site.
Recovery Cluster A cluster on which recovery of a package takes place following a failure on the cluster.
recovery group
failover
A failover of a package recovery group from one cluster to another.
recovery package The package that takes over on the Recovery Cluster in the event of a failure on the cluster.
rehearsal package The recovery cluster package used to validate the recovery environment and procedure as part
of a rehearsal operation.
remote failover Failover to a node at another data center or remote location.
resynchronization The process of making the data between two sites consistent and current once systems are restored
following a failure. Also called data resynchronization.
S
single system high
availability
Hardware design that results in a single system that has availability higher than normal. Hardware
design examples are:
• n+1 fans
• n+1 power supplies
• multiple power cords
• on-line addition or replacement of I/O cards, memory, etc.
special device file The device file name that the HP-UX operating system gives to a single connection to a node, in
the format /dev/devtype/filename.
split-brain
syndrome
When a cluster reforms with equal numbers of nodes at every site, and every half of the cluster
thinks it is the authority and starts up the same set of applications, and tries to modify the same
data, resulting in data corruption. Serviceguard architecture prevents split-brain syndrome in all
cases unless dual cluster locks are used.
SRDF (Symmetrix Remote Data Facility) A level 1-3 protocol used for physical data replication between
EMC Symmetrix disk arrays.
148 Glossary