Why am I getting SCSI errors when using device mapper multipathing with my MSA series and StorageWorks SAN?
by Josef WhiterThe MSA series and StorageWorks Storage Area Networks(SANs) are mostly active/passive SANs, which means that one path is always active, and the other path does not do anything until the active side fails. It is not possible to safely use device mapper multipathing on these SANs as it requires a special driver not provided with Red Hat Enterprise Linux 4. The vendor has a special firmware that will change the SAN to active/active which will allow it to work with device mapper multipathing. Please contact the vendor if you wish to use device mapper multipathing with this SAN.
