Designing a Disaster Tolerant Solution Using the Three Data Center Architecture
Designing a Disaster Tolerant Architecture Using Three Data Center with Continuous Access XP
Chapter 6 389
NOTE The Raid Manager configuration file must be different for each host,
especially for the HORCM_MON and HORCM_INST fields.
Creating Device Group Pairs
An application configured for an XP Three Data Center solution contains
two device groups; Continuous Access-Sync and Continuous
Access-Journal device groups. Both device group pair relations must be
established prior to the rest of the configurations and normal package
operations.
For a Multi-Hop data replication topology, first create the Continuous
Access-Sync pair. Then, create the Continuous Access-Journal pair after
completion of the Continuous Access-Sync pair creation. To create the
pairs use the following:
•Create Sync pairs of DC1-DC2 device group from any DC1 node:
— paircreate -g dg -vl -f data -c 15
or
— paircreate -g dg -vl -f never -c 15
•Create Journal pairs of DC2-DC3 once the DC1-DC2 device group
pairs are in “PAIR” state from any DC2 node:
— paircreate -g dg_1 -vl -f async -c 15 -jp 2 -js 2
For a Multi-Target data replication topology, the Continuous
Access-Sync and Continuous Access-Journal pairs can be created one
followed by another. Or they can be created at the same time. Use the
following to create the pairs:
•Create Sync pairs of DC1-DC2 device group from any DC1 node.
— paircreate -g dg -vl -f data -c 15
or
— paircreate -g dg -vl -f never -c 15
•Create Journal pairs of DC1-DC3 device group from any DC1 node
(You can verify whether they are in a “PAIR” state with the
pairdisplay command).