disks with non-unique device identifications

[Alan Casey]

I have allocated a new LUN from our SAN to this host
however when I go into SAM disk and devices I get the following error and am unable to allocate the disk to a VG
Any ideas??

SAM has detected unused disks with non-unique device identifications.These disks may have multiple hardware paths. If this is the case, use the Disk Devices Action "Mark Disk As Used" on the entries that correspond to additional hardware paths to prevent possible data corruption. 0/3/0/0/0/0.97.4.19.0.1.7 0/3/0/0/0/0.97.5.19.0.1.7 0/3/0/0/0/1.97.4.19.0.1.7 0/3/0/0/0/1.97.15.19.0.1.7

[Jeeshan]

Ho Alan

Which SAN you have?

Did you check the command pvdisplay /dev/dsk/cxtxdx ?

[Alan Casey]

Hi thanks,

looks like there is a problem with the san connection somewhere
pvdisplay: Couldn't find the volume group to which
physical volume "/dev/dsk/c5t1d0" belongs.
pvdisplay: Cannot display physical volume "/dev/dsk/c5t1d0".

I will go ask EMC... thanks

[Jeeshan]

That's better!

[TTr]

This may be perfectly normal. You could have up to 4 paths to a LUN in a SAN depending on the fiber connections and your zoning. It looks like the same LUN "...19.0.1.7" appearing under 4 paths.

Typically this happens when you have zoned the server port to both ports of the SAME controller of the array. And if you do this for EACH controller of the array you end up with 4 paths. LVM has no problem with it, although having 4 paths instead of 2 does not make it any safer. When there is a path failure in this case, two paths fail at the same time.

SAM is simply warning you in case the extra paths are used to output to these devices independently of each other.

Verify your zoning and if everything is good, use standard LVM commands, not SAM to set up your volume group.