After a temporary loss of any of the access path to the SAN, the path of the devices are deleted. The only way to recover is to reboot the server. This record is a problem for me. My operating system is RHEL 7.1

[root@host:/usr/sbin]# rpm -qa |grep -i multipath
device-mapper-multipath-libs-0.4.9-77.el7.x86_64
multipath-tools-0.4.9-7.7.x86_64
device-mapper-multipath-0.4.9-77.el7.x86_64

multipath.conf

device {
vendor "3PARdata"
product "VV"
path_grouping_policy "group_by_prio"
uid_attribute "ID_SERIAL"
path_selector "round-robin 0"
path_checker tur
features "0"
hardware_handler "1 alua"
prio "alua"
failback "immediate"
rr_weight "uniform"
no_path_retry 9
rr_min_io_rq 1
detect_prio yes
}