Using --type mirror LV mirroring, I could get information about which
physical disks that a given LV was on, by

 $ lvdisplay -m vgname/lvname

which would at least tell me the [hidden internal] LV names that the
mirror was distributed among; I could then

 $ lvdisplay -am vgname/lvname_mimage_{0,1}

to find them.

It seems that --type raid1 happens to use _rimage_$N as its image names,
but I only found that out by hunting around directly using

 $ dmsetup info | grep lvname

It would be good if similar information was displayed.
-----

That said, ideally it would be nice if such "cascaded" LVs would display
their component information, perhaps in a tree looking like this:



$ lvdisplay -avm vg_cel/root64
    Using logical volume(s) on command line
  --- Logical volume ---
  LV Path                /dev/vg_cel/root64
  LV Name                root64
  VG Name                vg_cel
  LV UUID                jcstwu-6f81-QcE8-dIl3-eSzo-VeQX-RRjU8D
  LV Write Access        read/write
  LV Creation host, time ,
  LV Status              available
  # open                 1
  LV Size                1.86 GiB
  Current LE             476
  Mirrored volumes       2
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:2