flow: 

# use user_friendly_names = no
- login to iscsi target
- run multipath -r 
- device appear with their original name

# use user_friendly_names = yes, configure some aliases
- run multipath -r 
- device appear with their alias name

# edit /etc/multipath.conf again, and change use user_friendly_names =
# no
- run multipath -r 
- device appear with their alias name

the rename should work backwards



# conf when using user_friendly_names = yes
defaults {
    polling_interval        5
    getuid_callout          "/lib/udev/scsi_id -g -u -d /dev/%n"
    no_path_retry           fail
    user_friendly_names     yes
    flush_on_last_del       yes
    fast_io_fail_tmo        5
    dev_loss_tmo            30
    max_fds                 4096
}

multipaths {

        multipath {
                wwid                36090a068a0746b89ddee943b5b253db6
                alias               rhev-a24-01_myDev1
        }
        multipath {
                wwid               36090a068a074fb95ddeee43b5b259da7
                alias               rhev-a24-01_myDev2
        }
}

# conf when using user_friendly_names = no

defaults {
    polling_interval        5
    getuid_callout          "/lib/udev/scsi_id -g -u -d /dev/%n"
    no_path_retry           fail
    user_friendly_names     no
    flush_on_last_del       yes
    fast_io_fail_tmo        5
    dev_loss_tmo            30
    max_fds                 4096
}