PV Alternative link.

[Tvs]

Hi all

I like to know more about pvlink. i know that it is for redundancy for the scsi controller. i want to know.

1. How we can create a alternate link for a pv

2. How the switch over is happening if one scsi controller fails.

3. How we can swap the alternative link and primary link

Regards

TVS

[Senthil Kumar .A_1 · Accepted solution]

Hi TVS,

The Answers are,

1. How we can create a alternate link for a pv

You do not require to create a PV link manually. All you have to do is added that device pathh to the vg as though it is a PV. Do not do a "pvcreate" as it was already do with the primary path.

ex: if /dev/dsk/c2t0d2 is pv linked to /dev/dsk/c4t0d2. then

vgcreate vg01 /dev/dsk/c2t0d2 , creates the vg.

Then, vgextend vg01 /dev/vg00/c4t0d2 is executed. LVM will automatically realize that it is a PV link, and adds it as a pvlink to the first disk. This can be seen in the vgdisplay -v output.

2. How the switch over is happening if one scsi controller fails.
The switch over happens automatically if the primary fails. It is taken care of by LVM subsystem, no manual intervention is required.

3. How we can swap the alternative link and primary link

Just remove the primary link with with vgreduce and add again.

vgreduce vg01 /dev/dsk/c2t0d2 and
vgextend vg01 /dev/dsk/c2t0d2.

The above sequence of command will swap the Primary and alternative link.

Regards,
Senthil Kumar .A

[Tvs]

Hi Senthil

Thnaks a lot.

can i get any documenmts regardsing this

thanks in advance

tvs

[Senthil Kumar .A_1]

Hi Tvs,

One of the useful links, I will add many more as I find it.

http://wwwpdp.web.cern.ch/wwwpdp/ose/file/hpux10/UNX1000071.html

Regards,
Senthil Kumar .A

[Victor BERRIDGE]

Hi
I would add for 3)
pvchange -s $PRIMARY # the new primary format:/dev/dsk/c...

Do a man of pvchange also...


All the best
Victor

[Tvs]

hi

the issue has been solved
thanks to all.

thanks to senthil and victor

regards

tvs