Replacing SAN switch

[john D_3]

Storage team is planning to replace existing SAN switch with DCX switch. HP UX 11.11 and 11.23 servers are connected. There will be no change on Storage array level.  All HP UX machines are connected with two paths. They will move first path and after few mintues second one. Does this change the device files? What are the precautions

Thanks 

[Torsten.]

Do the change online or offline (from hp-ux point of view).

The h/w path will change, so all LUNs will get new device files!

offline:

vgexport all the LUNs, install the new switches and do vgimport

online:

switch off one path, add the new path to each VG, then do the same on the other SAN. Finally remove the old path from the vg

[P Arumugavel]

Be cautious when you remove the paths from the VG.

Rgds...

[ayseif]

sorry, if i have same problem. but we already migrate 2 path go to new switch. now my vg not activated.

vgdisplay: Cannot display volume group "/dev/vgeva01".
vgdisplay: Volume group not activated.

[Bill Hassell]

>> now my vg not activated.

What did you do before moving the connections?

You should have run vgexport with the -s and -m  options to create a mapfile.

If you did not do anything, moving the connections has removed all the disk LUNs. You'll see this when you type vgdisplay.

Since the device files have changed, you'll need to run these commands:

umask 022
vgexport -m /etc/lvmconf/vgeva01.mapfile -s vgeva01
ioscan -fC disk
insf -C disk
mkdir /dev/vgeva01
mknod /dev/vgeva01/group c 64 0x100000
vgimport -m /etc/lvmconf/vgeva01.mapfile -s vgeva01
vgchange -a y vgeva01

Now all the above assumes there are no additional error messages and that the group file 0x100000 is a unique value. Be sure to copy all the messages on the screen if something doesn't work.