How to find Physical Volumes associated with a Logical Volume Group

mghiya · 02-21-2006, 06:58 AM

Regards

's

I am trying to find out all the Physical Volumes a Logical Volume Group is associated with.

I am able to get all the active Logical Volume(LV) Groups on the system through ioctl(VG_STATUS_GET_NAMELIST) and the Logical Volumes in the group through ioctl(LV_STATUS_BYINDEX). But I am unable to find out an ioctl call to get the Physical Volume associated with the LV Group.

I tried out the call, ioctl(VG_STATUS) which returns struct *vg_t which incidentally contains an array of pv_t* structures. But these structures are not populated by this call. How can I do this?

Any help is appreciated...

~Murtaza

macemoneta · 02-21-2006, 09:11 AM

Take a look at the code in lvdisplay's -m option. It performs mapping of logical to physical volumes:

Code:

# lvdisplay -m /dev/VolGroup00/LogVol00
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol00
  VG Name                VolGroup00
  LV UUID                KWqG5q-wFzR-2BJP-wxSF-sXTt-K7HF-r0R0pg
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                54.75 GB
  Current LE             1752
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:0

  --- Segments ---
  Logical extent 0 to 1751:
    Type                linear
    Physical volume     /dev/hda2
    Physical extents    0 to 1751

tizzef · 02-21-2006, 10:19 AM

You can issue a <pvscan> too.

$ pvscan
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- ACTIVE PV "/dev/sda2" of VG "root_vg" [14.64 GB / 7.17 GB free]
pvscan -- ACTIVE PV "/dev/sda4" of VG "omgr_vg" [15.26 GB / 0 free]
pvscan -- total: 2 [29.92 GB] / in use: 2 [29.92 GB] / in no VG: 0 [0]
$

Cheers