The CA Spectrum 10.3 release provides support for moving the mysql myisam db to the innodb engine. The innodb allows for performance improvements with Spectrum's mysql however it has been noticed that after converting the mysql db from myisam to innodb the mysql db grew 40% in disk space.
Release: Spectrum 10.3.0 and greater
This is expected behavior due to changes with the InnoDB engine. The post installation steps for CA Spectrum 10.3 note the increase in disk size when using InnoDB. Pleae reference the "Post Upgrade Tasks" section of the documentation for more information.
After conversion, the InnoDB tables occupy more space (approxamity 30%-40%) compare to the MyISAM tables. As per MYSQL recommendation, the InnoDB is considered as the most efficent engine to work on large scale tables. The InnoDB supports row level locking and auto crash recovery features, which are not supported in MyISAM.