Exchanging the central Storage System during Operations

Abstract

The ISS Columbus Ground Segment is a complex system with several subsystems using a central Storage Area Network (SAN). The Project operates 24/7. Therefore the migration from old to new hardware had to be performed without any interruption to operations. The migration became necessary because the subsystems’ software has to be updated together with an update of the operating system. With the complexity of the old SAN that would only have been possible with 4 to 6 week interruption to ongoing operations. To avoid such a situation in the future, it was decided to replace the system completely and to use the K.I.S.S. approach (Keep It Simple and Stupid) for the new system design. The Columbus system uses a variety of different applications running on different operating system versions. Projecting this into the future, it is very important to be able to update the storage system while maintaining the subsystems independently.