Building Disaster Recovery Serviceguard Solutions Using Metrocluster with EMC SRDF

Q
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.
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.
RDF-ECA (RDF Enginuity Consistency Assist) A Solutions Enabler feature to provide consistency protection
for SRDF/Synchronous devices. RDF-ECA is used for M by N Symmetrix configurations using
Metrocluster with EMC SRDF.
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 after the systems are
restored following a failure. Also called data resynchronization.
S
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.
SRDF (Symmetrix Remote Data Facility) A level 1-3 protocol used for physical data replication between
EMC Symmetrix disk arrays.
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.
Symmetrix device
number
The unique device number that identifies an EMC logical volume.
synchronous data
replication
Each data replication I/O waits for the preceding I/O to complete before beginning another
replication. Minimizes the chance of inconsistent or corrupt data in the event of a rolling disaster.
T
transparent
failover
A client application that automatically reconnects to a new server without the user taking any
action.
U-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 unless you
are using Serviceguard OPS Edition. 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.
WAN data
replication
solutions
Data replication that functions over leased or switched lines.
134 Glossary