topic Re: PV link in Operating System - HP-UX

PV link

Sofiane LARDJANE — Wed, 17 May 2006 11:22:01 GMT

Hi all,

I have An rp4440 with 11.23 OS installed, eva 4000 and 2 san switches. I present a disk from eva to the rp4440 and I can show this disk through 4 different paths with ioscan (2 paths for each HBA). I didn't have secure path so I use pv link. My question : Can I have 1 primary and 3 alternate paths ? If yes, how can I do this ?

Thx in advance,

Sofiane.

Re: PV link

Steven E. Protter — Wed, 17 May 2006 11:33:48 GMT

Shalom Sofiane,

http://docs.hp.com/en/B2355-90672/ch03s11.html

http://docs.hp.com/en/B2355-90672/index.html

SEP

Re: PV link

Ninad_1 — Wed, 17 May 2006 11:37:11 GMT

Yes you can have upto 1 primary and 7 alternate paths.
You can do this using the vgextend command.
e.g. If you have created /dev/vgxx with a disk /dev/c0t6d0 and want to configure the alternate links -
vgextend /dev/vgxx /dev/dsk/c1t6d0 /dev/c2t6d0 /dev/c3t6d0
The disks mentioned are the device names for the alternate paths
LVM automatically treats them as alternate links as it knows that they are the same disk device with different paths.

Regards,
Ninad

Re: PV link

James R. Ferguson — Wed, 17 May 2006 11:39:22 GMT

Hi:

You may have up to eight (8) pathes to a physical disk with LVM.

To add alternate (pvlinks) simply:

# vgextend /dev/vgNN /dev/dsk/cXtYdZ

The first path to a physical disk is the primary and others are alternate or secondary ones available for fail-over. To exchange an alternate link to a primary one, 'vgreduce' the primary link and then 'vgextend' it back into the volume group.

Regards!

...JRF...

Re: PV link

rariasn — Thu, 18 May 2006 02:12:17 GMT

Hi Sofiane,

Sample "vgextend",

# vgdisplay vgsample

...

--- Physical volumes ---
PV Name /dev/dsk/c25t0d1
PV Status available
Total PE 2156
Free PE 7
Autoswitch On

#vgextend vgsample/dev/dsk/c26t0d1
Volume group "vgsample" has been successfully extended.
Volume Group configuration for /dev/vgsample has been saved in /etc/lvmconf/vgsample.conf

# vgdisplay vgsample

--- Physical volumes ---
PV Name /dev/dsk/c25t0d1
PV Name /dev/dsk/c26t0d1 Alternate Link
PV Status available
Total PE 2156
Free PE 7
Autoswitch On

Add all alternates disks,

# vgextend /dev/vgsample /dev/dsk/cxtydz /dev/dk/... ...

rgs,

ran

Re: PV link

BUPA IS — Thu, 18 May 2006 07:12:40 GMT

hello,
you can make one of the alternates become the primary for that disk using the pvchange command without taking the vg down
pvchange -s -A y /dev/dsk/cxxtydn the disk in the command becomes the primary link and the others revert to being alternate links .
regards
Mike.