How do you add an alternate link ?

[Mark A. Smith]

Running HPUX 11.11, I want to add an
alternate link to a current Volume Group

PV Name /dev/dsk/c7t3d5
PV Status available
Total PE 1935
Free PE 1636
Autoswitch On

To extend that, is the command
vgextend /dev/vgsb1 /dev/dsk/cXtXdX

So it looks like:

PV Name /dev/dsk/c7t3d5
PV Name /dev/dsk/c9t3d5 Alternate Link
PV Status available
Total PE 1935
Free PE 0
Autoswitch On

[Rajeev Tyagi]

Mark,

Do vgextend /dev/vgsb1 /dev/dsk/c9t3d5. you do not need to do pvcreate again.

Rajeev

[Mark A. Smith]

Rajeev,

How can I be sure which disk I can use as an alternate ?

[Rajeev Tyagi]

Mark,

You should have map from your storage Engineer. Otherwise when you do vgextend for a physical volume without pvcreate if it is an alternate link volume group will be extended successfully and you can verify with vgdisplay -v command.

[Mauro Gatti]

Alternate link has same target and same lun ID but differente card instance.
So, if you know for example that card 1 and card 5 go on same storage box on same controller you will see
c1tXdY and c5tXdY
Same couple of X,Y values will address same disk.

[Rajeev Tyagi]

Mark,

Otherway of doing this is.

Add first path to volume group.

#vgextend /dev/vgsb1 /dev/dsk/c7t3d5

Read VGID from both disk

#echo 0x2010?2X | adb /dev/dsk/c7t3d5 | awk '{print $3}'

#echo 0x2010?2X | adb /dev/dsk/c9t3d5 | awk '{print $3}'

If both match that means they are pointing to same physical disk.

#vgextend /dev/vgsb1 /dev/dsk/c9t3d5

Confirm with vgdisplay -v.

Hope this helps...