50 Migrating Siebel Database from DB2/Oracle for NT to DB2 for OS/390
This is the outline of the process required to migrate a DB2 for NT server to a
DB2 for OS/390 server. Additional planning is required to put this in production.
Authorization, backup and restore, disaster recovery, and performance tuning all
have to be examined and merged into the current DB2 for OS/390 production
It took 8 to 12 hours for the Siebel DB2 for OS/390 DBA to move 40 GB of data
from DB2 for NT using DSNTIAUL running on OS/390. This was an early attempt
and times have improved since. The additional time for the first move was
because the operation was not optimized for DASD space usage. We estimate
that this time can be cut to 4 to 6 hours with sufficient SMS-managed DASD.
To unload the approximately 1800 Siebel tables, the DSNTIAUL jobs were split
into 18 physical jobs. DSNTIAUL can only take SYSREC00 - SYSREC99, so
divide the number of tables by 100 for the number of jobs.
In our case, we run four job streams at a time mainly due to the amount of DASD
available for DB2's usage. You will have to adjust the number of parallel streams
based on the amount of DASD available for the SORTOUT, SYSUT1,
SORTWK01- SORTWK08 datasets. You can experiment to see how many jobs
can be run in parallel or you can go through the exercise of calculating the exact
amount of DASD required using the formulas in the DB2 manuals. There is no
simple formula since you have to take into account the number of rows, the
number of indexes, and the sizes of indexes. The JCL attempts to handle the
largest table so for most tables the allocation amounts may seem high but you
have to be ready for peak demands if you want to run this process unattended.
To reload the data into DB2 for OS/390 after the unload, figure between 6 to 12
hours for the 40 GB. Run 4 jobs at a time that have multiple tables per job. They
may clash on table space, DASD, core, etc. They need to be monitored for
continuous processing. Again, having enough SMS-managed DASD helps speed
things up. The loads include “resume yes”, indexes, and a lot of buffers (250 on
input data sets and works and sorts); also specify external sorts (24). The total
time includes parallel RUNSTAT jobs (4) after all the loads, but does not include a
3.7 DB2 family cross-loader function
The DB2 family cross-loader function is an alternative to the scenario described
in the previous section, and available only in the DB2 for OS/390 V7
environments. It is a powerful data migration tool for the DB2 family.
Chapter 3. Migrating Siebel data from DB2 for NT to DB2 for OS/390 51
With DB2 for OS/390 Version 7, the DB2 LOAD utility is enhanced to support the
use of SQL SELECT to produce input directly into LOAD. This enhancement
delivers a DB2 family cross-loader function. With DB2 for OS/390 Version 7, you
can use any DRDA-compliant database server as a data input source for
populating your tables in DB2 for OS/390. Your input can even come from
non-DB2 data sources by using DataJoiner for access to data from sources as
diverse as Oracle and Sybase, as well as the entire DB2 family of database
Siebel 2000 is not currently supporting DB2 for OS/390 V7, but is likely to do it at
a later time. The DB2 family cross-loader function will be available to Siebel
Systems as soon as it supports DB2 for OS/390 V7.
For more information on the Cross Loader refer to DB2 UDB for OS/390 and
z/OS Utility Guide and Reference Version 7, SC26-9945, and the redbook DB2
UDB Server for OS/390 and z/OS Version 7 - Presentation Guide, SG24-6121.
52 Migrating Siebel Database from DB2/Oracle for NT to DB2 for OS/390