SG and Alternate paths

[J Turner]

Here is the issue. Our server was built and the SANS disk presented to the server before we were aware that it would be a high availabilty server.
Because of this the Primary and Alternate links for the two dik presented are on the same two port FC. So Disk1 Primary and Alternate is on path 2/0/1/1.
Disk2 Primary and Alternate are on 2/0/2/1
What I have requested of the SANs team is to unpresent the Alternate path (The disk already have a Data Base on them) And then represent them to the WWNs that I have sent them.
This would have the Primary for Disk1 on on 2/0/1/1 with the Alternate path for Disk2.
Disk2 Primary will still be on 2/0/2/1 with the Alternate for disk1.

Are there any major changes that will need to be done to my VG groups or lvmtab or?
Any advice or heads up is appreciated.
OS HPUX 11.23
Storage XP

thanks

[TTr]

Most likely the device files will change so

A. if there is no data on the LUNs, vgexport all the VGs and have the SAN group remap the LUNs and recreate (or vgimport) the VGs.

or

B. If you have data on the LUNs already,
1. backup all the data
2. vgexport all VGs
3. SAN team unmap the LUNs and remap them
4. Get new device files
5. vgimport all LUN devices in each VG in the right order

[J Turner]

Ok so I create the vgexport file.
Can I edit it to replace the Alternate links?
How do I change the links inside the file?
Also, can the primary links stay active while I change the Alternate links.
Thanks.

[J Turner]

Also, I can NOT assign points at this time for some reason.
But it will happen!

[TTr · Accepted solution]

No need to edit anything, you specify the new disk device paths in the vgimport command line.

When you are ready to do this you can unmount any filesystems if you have mounted and then deactivate the VGs (vgchange -a n...) and wait until the remapping is done. If the device paths do not change you simply reactivate the VGs. If the paths change you 'll have to go through the entire process vgexport...

Just in case the paths do not change, you 'll save some work. I had a case last week where I did some remapping, the LUN numbers remained the same on the new mapping but the paths changed.

[likid0]

the thing is, before they remove the alternate path, you have to vgreduce it.

so lets say 2/0/1/1 is disk /dev/dsk/c2t0d1 primary
and 2/0/2/1 is disk /dev/dsk/c4t0d1 alternate

you should:

vgreduce /dev/yourvg /dev/dsk/c4t0d1
make the change on the san
ioscan -fC disk
insf -C disk
xpinfo -il | grep -i yourdiskid
vgextend /dev/yourvg /dev/dsk/yournewdisk


in case you are using any disk on the 2/0/2/1
as a primary.you have to change it with

pvchange -s /dev/dsk/thepathyouwhant to make primary

[J Turner]

Thanks
vgreduce to remove Alternate paths
vgexport w mapfile and vgid
vgimport after SAN work.
All good and many thanks.