How to use the LUN of one HP-UX server to another server

[Gordon Sjodin]

The vgexport command on the source server is done to export all of the logical volume information.
After you have imported the vg onto the new server make sure you run a vgexport again on the source server to remove the volume group otherwise you could have two systems accessing the file system at the same time.

[Torsten.]

>> removing the LV, and then removing the vgXX, <<

Be careful, remove the LV and VG means deleting the data!

vgexport will remove all the configuration information from the server, but not from the data disks.

[Rita C Workman]

I will presume you are NOT in a failover environment.

First, make sure that the lun is 'masked' over to the new server. This is SAN work. Confirm that every disk is masked to that new server and device files were created.

Next...with the old server up and seeing the disk, run the commands that Pete and others gave you to create mapfiles (vgexport).
On the new node run the commands to mkdir/mknod & vgimport. Stop - don't run vgchange just yet.

Umount all f/s affected on the old server, and then run vgchange -a n /dev/.

Now your data is still there on the disk.

Now go over to the new server. You already ran vgimport command, so now just run vgchange -a y /dev/ and see if you can manually mount the f/s.
Once all is up okay and mounted, remember to add to your /etc/fstab.

When your done with the old server - then from the old server you can do the cleanup if you like:
vgexport /dev/ removes it from /etc/lvmtab
remove entries from /etc/fstab
'unmask' disks from old server

Rgrds
Rita

[Rita C Workman]

Boy you think you didn't miss a step.

Before you run vgchange -a y on the new server, go to the old server and run vgchange -a n

ok...now I'm done

Rita

[senthil_kumar_1]

Hi All,

1)Shall i change the name of VG in destination.

For exampled:

In source = /dev/vg01

In destination = /dev/vg04

Is it possible?

2)Has both major and minor numbers to be same?

[Rita C Workman]

You can change the minor number and/or the volume group name on the new server.

Rita

[senthil_kumar_1]

Hi All,

I have some following questions:

1)Do we need to map all the LUNs to destination server if the VG is having lot of LUNs in source?

2)Can we map one LUN of VG (that VG is having more LUNs in source) to destination and get the LVs of that LUN in destination?

3)What i have to do if i want failover, plesase explain the steps?

[Gordon Sjodin]

You may want to consider just doing a backup and restore if you want to be selective of the data set.

[senthil_kumar_1]

Colud you please answer my questions one by one.

[sujit kumar singh]

Hi



1)Do we need to map all the LUNs to destination server if the VG is having lot of LUNs in source?

yes you need to do, otherwise there cane be few disks in the new Vg on new node and there shall be problems of VG activation if quorum check fails.

2)Can we map one LUN of VG (that VG is having more LUNs in source) to destination and get the LVs of that LUN in destination?

it depends how that lun is having data on that.
if that LUN is a part holding any spanned or striped logical volume, you will not get the data on that if you try to use that as it shall not find other members of the Stripped/ spanned LV. so you shall corrupt data.

also say the source VG has 4 LUNs and you use only 1 LUN for Impoerting in a new VG, the VG shall fail quorum check on activation.

if you have 2 LUNs and all the LVs on that LUN are non-striped as well as non-spanned and the LVs on one LUN are mirrored to that on the second LUN and assuming this is not a root VG, you can use one LUN to import VG and activate the VG in quorum override mode and may get the data.

so this is all that "depends".


3)What i have to do if i want failover, plesase explain the steps?

can you be more clear for this question, what type of failover?


regards