Updated device-mapper-multipath packages that resolve an issue are now available for Red Hat Enterprise Linux 6.
The device-mapper-multipath packages provide tools to manage multipath devices by giving the "dm-multipath" kernel module instructions on what to do, as well as by managing the creation and removal of partitions for Device-Mapper devices.
When all paths of a pathgroup with set group_by_prio were restored after a failure, multipathd could place some paths into a wrong pathgroup. This issue occurred, because the daemon checked if pathgroups needed reconfiguration only if a path priority changed. When the original paths were restored, they could have been assigned the same priority as before the failure. In such case the paths were incorrectly left in a wrong pathgroup. With this update, when checking if it needs to recalculate the pathgroups, the multipathd daemon refreshes and checks all priorities once a new path becomes available and places recovered paths into the correct pathgroup.
All users of device-mapper-multipath are advised to upgrade to these updated packages, which resolve this issue.