I've once tried to replicate a few tables from DB2 (z/OS) to MySQL through an application (running on Linux and connecting to both DB2 and MySQL through ODBC; it took terribly long (and consumed an unexpected amount of CPU on the mainframe).
After that, I used UNLOAD in DB2 to produce a CSV file, then ftp-ing that file to Linux where I LOAD it into MySQL; all this takes about 100x less time than the first method.
Here are the exact statements:
DB2 utility command:
UNLOAD DATA FROM TABLE mytbl DELIMITED CHARDEL X'7D' UNLDDN filename
Ftp commands:
ASCII
SITE 'charset(sw88591)'
GET filename
BYE
MySQL command:
load data local infile 'filename' replace into table mytbl character set latin1 fields terminated by ',' optionally enclosed by '''';