When planning for SQL Replication, you might need to consider planning
for migration, memory, storage, conflicts, source systems, code page conversion,
and performance.
Migration planning
Planning migration involves planning for issues that might arise
while migrating from one version of replication to another.
Memory planning
Memory planning involves planning for the amount of memory required
by replication. Replication uses memory only as needed. The amount of memory
required is directly proportional to how much data is being replicated from
the source and the concurrency of the transactions. Basically, the more data
that is being replicated and the more concurrent transactions you have, the
more memory is required by replication.
Storage planning
Storage planning is important for log impact for DB2® source servers,
log impact for target servers, storage requirements of target tables and control
tables, space requirements for diagnostic log files (Linux, UNIX, Windows, z/OS®),
space requirements for spill files for the Capture program, and space requirements
for the spill files for the Apply program.
Conflict detection planning
If you use standard or enhanced conflict detection, you must store
before-images in the CD (or CCD) tables for the replica target tables. Also,
the referential integrity rules are restricted. In peer-to-peer and update-anywhere
scenarios, or when the Apply program uses transaction mode processing, you
should define referential integrity rules that are in keeping with the source
rules. If you use peer-to-peer replication or update-anywhere replication
and you do not want to turn on conflict detection, you should design your
application environment to prevent update conflicts. If conflicts cannot occur
in your application environment, you can save processing cycles by not using
conflict detection.
Non-DB2 relational source planning
Capture triggers are used instead of the Capture program if you
are replicating from non-DB2 relational databases. These triggers capture
changed data from a non-DB2 relational source table and commit the changed
data into CCD tables.
Code page conversion planning
Replication components are database applications that rely
on the DB2 databases on various operating systems to
handle conversion of data that uses different code pages.