San-switch cascading

[chindi]

hi ,

We have two san-switches 4/16 and 8/40 brocade.

We would like to cascade this 2 san-switches.

After cascading one san switch with other what we have observed that we are able to acess storage from other san-switch.

Whereas other san-switch which is cascaded , has got different paths , which we are not able to vgextend on existing vg's .

We are getting :

root #/ >vgextend vg_day_db /dev/dsk/c11t0d5 /dev/dsk/c13t0d5
Couldn't open physical volume "/dev/rdsk/c5t0d5":
Verification of unique LVM disk id on each disk in the volume group
vg_day_db failed.

Out of which specified two paths from new san switch  8/40 which is cascaded with  4/16 san-switch .