When integrating Linux hosts into Storage Area Networks (SANs), the multipathing challenge, which has been rather academic in SCSI, becomes real. On the one hand due to network and host adapter failover reasons multiple SAN ports exist on the host side, and on the other hand modern SAN capable storage devices connect to the SAN via multiple device ports, which additionally results in improved bandwidth.

Various approaches exist to implement a solution in Linux, e.g. patches to MD, or the SCSI mid-level code, concurring with approaches deploying the volume management system EVMS. We have chosen to enhance LVM's grouping and dispatching services to be capable of managing device path groups beyond device groups and present a solution that brings failover and load balancing capabilities to the SCSI (and o ther attachment) stacks, only being based on LVM infrastructure.

Stefan Bader received a Diploma in Computer Science in 1994. He joined IBM as a consultant for AIX Systems Management and since 2001 is working on the mainframe port of Linux in the Boeblingen Development Labs with a focus on Storage Networking Solutions.