Red Hat

[root@whatever_server device]# multipath -l
mpath0 (36000097000019260298953666633436) dm-11 EMC,SYMMETRIX
[size=40G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=0][active]
 \_ 2:0:0:9     sda 8:0   [active][undef]
 \_ 3:0:0:9     sdb 8:16  [active][undef]
 \_ 2:0:0:32777 sdc 8:32  [active][undef]
 \_ 2:0:0:32793 sdd 8:48  [active][undef]
 \_ 3:0:0:32777 sde 8:64  [active][undef]
 \_ 3:0:0:32793 sdf 8:80  [active][undef]
 \_ 2:0:0:36873 sdg 8:96  [active][undef]
 \_ 2:0:0:36889 sdh 8:112 [active][undef]
 \_ 3:0:0:36873 sdi 8:128 [active][undef]
 \_ 3:0:0:36889 sdj 8:144 [active][undef]
 \_ 2:0:0:40969 sdk 8:160 [active][undef]
 \_ 2:0:0:40985 sdl 8:176 [active][undef]
 \_ 3:0:0:40969 sdm 8:192 [active][undef]
 \_ 3:0:0:40985 sdn 8:208 [active][undef]
 \_ 2:0:0:45065 sdo 8:224 [active][undef]
 \_ 3:0:0:45065 sdp 8:240 [active][undef]
 \_ 2:0:0:45081 sdq 65:0  [active][undef]
 \_ 3:0:0:45081 sdr 65:16 [active][undef]

[...]
multipaths {
        #----------------- [dbvg Start] ----------------------
        multipath {
                wwid                    360050768018200878000000000000108
                alias                   dbvgpv01
        }
        multipath {
                wwid                    360050768018200878000000000000140
                alias                   dbvgpv02
        }
        #----------------- [dbvg End] -------------------------
        #----------------- [appvg Start] ----------------------
       multipath {
                wwid                    360050768018200878000000000000149
                alias                   appvgpv01
        }
        #----------------- [appvg End] ------------------------
}
[...]

root@host # ls -l /dev/mpath
total 0
lrwxrwxrwx 1 root root 8 Jun 20 12:31 dbvgpv01 -> ../dm-13
lrwxrwxrwx 1 root root 8 Jun 20 12:31 dbvgpv01p1 -> ../dm-21
lrwxrwxrwx 1 root root 8 Jun 20 12:31 dbvgpv02 -> ../dm-14
lrwxrwxrwx 1 root root 8 Jun 20 12:31 dbvgpv02p1 -> ../dm-20
lrwxrwxrwx 1 root root 8 Jun 20 12:31 appvgpv01 -> ../dm-11
lrwxrwxrwx 1 root root 8 Jun 20 12:31 appvgpv01p1 -> ../dm-17
[...]

[...]

devices {
    [...]
    # An array of directories that contain the device nodes you wish
    # to use with LVM2. "/dev" is for the local disk(s) /dev/sda, /dev/sdb,
    # etc., "/dev/mpath" is for the SAN disks

    scan = [ "/dev", "/dev/mpath" ]

    # filter rules are basically regexps. "a|" means "accept", "r|" means "remove".
    # The rules in detail:
    # "r/.*/" removes every device not explicitly allowed by the rules before
    #
    # "a|vg[0-9]*pv[0-9]*|" my VG names always end in "vg", sometimes followed by a number
    # allow everything ending in "vg" or "vg<nr>" followed by "pv<nr>" like
    # "appvgpv01" or "db5vgp03", etc.
    #
    # "a|sd[ab]$|", "a|sd[ab][1-9]*$|" allows "/dev/sda" or "/dev/sdb",
    # both optionally followed by a number (/dev/sda1), but NOT a
    # character. This filters out "/dev/sdaa" and similar devices.

    filter = [ "a|vg[0-9]*pv[0-9]*|", "a|sd[ab]$|", "a|sd[ab][1-9]*$|", "r/.*/" ]

    [...]
}