topic Re: vgextend neccessary in Operating System - HP-UX

vgextend neccessary

Arnulf Gercke — Sun, 26 Jun 2005 07:15:54 GMT

Hello,

customer has an rp3440 connected with one FC HBA to a SAN switch.
Storage Device is VA7400. LUNs from the VA are seen once on the rp3440.
Now we want to connect a second FC HBA in the rp3440 to a second SAN switch.
I know, that multipathing can be done by HP-UX PV-Links.
But customer wants to install Secure Path VA (formerly known as Autopath VA).
After Installing Secure Path, do I need a vgextend to the new LUN-Devices
or does Secure Path handle it all?

Re: vgextend neccessary

Victor Fridyev — Sun, 26 Jun 2005 07:46:12 GMT

Hi,

You have to extend volume groupd by yourself.
It's simple:

vgextend vgname /dev/dsk/XXXX ,

where /dev/dsk/XXXX is the disk name from the alternate path.

HTH

Re: vgextend neccessary

Senthil Kumar .A_1 — Sun, 26 Jun 2005 10:23:44 GMT

Hi Arnulf,

Though not too sure of my statement..

But heard "Only VXVM can automatically recognize the pv link's, but LVM subsystem need to be made aware of by explicitly through - vgextend "

Regards

Re: vgextend neccessary

vinod_25 — Sun, 26 Jun 2005 23:05:22 GMT

hi Arnulf

AutoPath and pvlinks provide the same features, except that AutoPath
also includes the load balancing feature. For the AutoPath configuration,
you would set the physical volume to point to the AutoPath device file and
not the raw or character device file. You use AutoPath OR pvlinks, not
both. If you set up both, one would timeout to the other and you would curl up and die.

Regards

Vinod K

Re: vgextend neccessary

Devender Khatana — Sun, 26 Jun 2005 23:14:26 GMT

Hi,

LVM do not detect alternate links by itself. You need to extend VG to all alternate paths. If you are adding only one then for the same.

If you have multiple LUNS configured in your VG's then a good idea will be to use one path as paimary path for half disks & second path as primary path for other half no. of disks. This will allow both paths to be used while trying VG. Otherwise LVM do not support load balancing over multiple path & works in active-standby mode.

HTH,
Devender

Re: vgextend neccessary

Arnulf Gercke — Sun, 26 Jun 2005 23:21:12 GMT

Hi vinod,
but in install guide for secure path, i found the following:

Secure Path SAN Boot Set Up for XP and VA Devices
Use the following procedure for the Secure Path SAN Boot setup sequence:
1. Install HP-UX OS 11i v1.0 or 11i v2 on the XP or VA LUN and boot the
system.
2. Install Secure Path on the Boot LUN.
3. Configure LVM with alternate physical volume paths to the primary boot
volume path.
4. Use the autopath display command to record alternate paths to the
primary boot volume path.
# vgextend /dev/vg00
Example:
# vgextend /dev/vg00 /dev/dsk/c14t0d1 /dev/dsk/c16t0d1
/dev/dsk/c18t0d1
The vgextend command extends root volume with alternate paths.

Re: vgextend neccessary

Arnulf Gercke — Wed, 10 Aug 2005 17:41:41 GMT

Found out, that vinod's answer is the correct one.
"You use AutoPath OR PVLinks, not both."
That's it.