[linux-lvm] lvconvert parameters to remove mirror

[ben scott <benscott nwlink com>]

I have a question about how to remove a mirror. On a test
set up I have the following mirrors:

  bedroom:~/kvpm# lvs --all --segments -o +devices
    LV               VG    Attr   #Str Type   SSize  Devices
    lvol0            trurg mwn-a-    3 mirror 23.68G lvol0_mimage_2  
(0),lvol0_mimage_1(0),lvol0_mimage_3(0)
    [lvol0_mimage_1] trurg iwi-ao    1 linear 23.68G /dev/hdg6(155008)
    [lvol0_mimage_2] trurg iwi-ao    1 linear 19.53G /dev/hde2(0)
    [lvol0_mimage_2] trurg iwi-ao    1 linear  4.15G /dev/hdg5(0)
    [lvol0_mimage_3] trurg iwi-ao    1 linear 23.68G /dev/hde3(0)
    [lvol0_mlog]     trurg lwn-ao    1 linear 64.00K /dev/hde1(0)


So to remove the mirror "[lvol0_mimage_1]" on /dev/hdg6
I do the following:

  bedroom:~/kvpm# lvconvert --mirrors -1 trurg/lvol0   /dev/hdg6
    Logical volume lvol0 converted.

  bedroom:~/kvpm# lvs --all --segments -o +devices
    LV               VG    Attr   #Str Type   SSize  Devices
    lvol0            trurg mwn-a-    2 mirror 23.68G lvol0_mimage_2
(0),lvol0_mimage_3(0)
    [lvol0_mimage_2] trurg iwi-ao    1 linear 19.53G /dev/hde2(0)
    [lvol0_mimage_2] trurg iwi-ao    1 linear  4.15G /dev/hdg5(0)
    [lvol0_mimage_3] trurg iwi-ao    1 linear 23.68G /dev/hde3(0)
    [lvol0_mlog]     trurg lwn-ao    1 linear 64.00K /dev/hde1(0)

And indeed it is gone. However when I do this:

  bedroom:~/kvpm# lvconvert --mirrors -1 trurg/lvol0   /dev/hde2
    No free extents on physical volume "/dev/hde2"
    No specified PVs have space available

Or this:

  bedroom:~/kvpm# lvconvert --mirrors -1 trurg/lvol0   /dev/hde2 /dev/hdg5
    No free extents on physical volume "/dev/hde2"
    No mirror images found using specified PVs.

So how do I delete a mirror that spans multiple segments? Wouldn't it make
sense to have a command such as:

  bedroom:~/kvpm# lvconvert --mirrors -1 trurg/lvol0  [lvol0_mimage_2]

Thank you for any help.