Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Building a Continental Cluster
Designing a Disaster Tolerant Architecture for use with ContinentalClusters
Chapter 5196
Logical data replication may require the use of packages to handle
software processes that copy data from one cluster to another or that
apply transactions from logs that are copied from one cluster to another.
Some methods of logical data replication may use a logical replication
data sender package; others may use a logical replication data
receiver package; some may use both. Logical replication data sender
and receiver packages are configured as part of the data recovery group,
as shown below under “Creating the ContinentalClusters
Configuration.”
Physical Data Replication using Special Environment files
For physical data replication ContinentalClusters had two
pre-integrated solutions. One used XP/CA and other used EMC/SRDF. In
order to use these data replication solutions in a ContinentalClusters
environment you will need to purchase the MetroCluster/CA or
MetroCluster/SRDF products separately.
Physical data replication generally does not require the use of separate
sender or receiver packages, but it does require specialized logic in the
package control scripts to handle the transfer of control from the storage
units of one cluster to the storage units at the other cluster. The
packages that use physical data replication with the HP StorageWorks E
Disk Array XP Series with Continuous Access XP should have created a
specific environment file using template
/opt/cmcluster/toolkit/SGCA/xpca.env; for packages that are using
physical data replication with EMC Symmetrix and the SRDF facility
should be created using /opt/cmcluster/toolkit/SGSRDF/srdf.env.
Physical
Replication of
Disk Units via
Hardware
Replication of the LUNs
within a disk array
through dedicated
hardware links such as
EMC SRDF or
Continuous Access XP.
Limited CPU requirements,
but the requirement of
synchronous data
replication slows
replication, and may impair
application performance.
Increased network speed
and bandwidth can remedy
this.
Table 5-3 Data Replication and ContinentalClusters (Continued)
Replication
Type
How it Works
ContinentalClusters
Implication