Solaris Multiplexed I/O (MPxIO), also known as Sun StorageTek Traffic Manager, is multipath I/O software integrated into the Solaris and illumos operating systems since Solaris 8 (2000). MPxIO allows a storage device to be accessed via multiple host controller interfaces from a single OS instance, providing protection against I/O outages by automatically switching to an alternate controller if one fails. It also improves I/O performance through load balancing across channels. In Solaris 10, the configuration to enable or disable MPxIO was moved from /kernel/drv/scsi_vhci.conf to the end of /kernel/drv/fp.conf and /kernel/drv/mpt.conf.