Checking extends distribution of Logical Volumes against Physical Volumes

Bonjour,

I desperately search how to see how the extends of a Logical Volume are distributed on the disks that make up the Volume Group. Especially when the Logical Volume is mirrored between 2 different storage array.

The idea behind this check is :

- to detect if a logical volume is mirrored on two volumes from a same array
- to verify wich extends are not synchronized

I had a case where one of my client configured a volume group with several disk from a given array, several from a second array, and has created a logical volume mirrored on the same array ... :-(

Under HP-UX we can simply control the localisation of extends of a logical volume whith lvdisplay and -v option. It doesn't work under Linux.

Exemple with vg01 which owns 2 disks from an array (disk12 en disk23) and 2 disks from another array (disk114 and disk142)

root@kskckca:/# lvdisplay -v /dev/vg01/lvol1
--- Logical volumes ---
LV Name                     /dev/vg01/lvol1
VG Name                     /dev/vg01
LV Permission               read/write
LV Status                   available/syncd
Mirror copies               1
Consistency Recovery        MWC
Schedule                    parallel
LV Size (Mbytes)            69988
Current LE                  17497
Allocated PE                34994
Stripes                     0
Stripe Size (Kbytes)        0
Bad block                   NONE
Allocation                  strict
IO Timeout (Seconds)        default

   --- Distribution of logical volume ---
   PV Name                 LE on PV PE on PV
   /dev/disk/disk12        17497    17497
   /dev/disk/disk114       17494    17494
   /dev/disk/disk23            3        3

      --- Logical extents ---
   LE       PV1                PE1      Status 1 PV2                PE2      Status 2
   00000000 /dev/disk/disk12   00000000 current  /dev/disk/disk114  00003821 current
   00000001 /dev/disk/disk12   00000001 current  /dev/disk/disk114  00003822 current
   00000002 /dev/disk/disk12   00000002 current  /dev/disk/disk114  00003823 current
   .../...
   00017494 /dev/disk/disk12   00017494 current  /dev/disk/disk23   00006241 current
   00017495 /dev/disk/disk12   00017495 current  /dev/disk/disk23   00006242 current
   00017496 /dev/disk/disk12   00017496 current  /dev/disk/disk23   00006243 current

Here I can see that almost all extends of this LV are mirrored between disk12 (my first test array) and disk114 (a volume from a second array). OK.
BUT the last 3 extends of the LV are mirrored between disk12 and disk23 ... that reside on the same storage array. Not good :-(

I can also see that all extends are synchronised : status = current

Is there anyway to get those useful informations under Linux ? I currently work with a Red Hat 7.3

Many thanks in advance

Eric