How to change a fc target with ServiceGuard

[Carme Torca]

Hi,

I have ServiceGuard A.11.17.00, with two servers. Now I have all the packets in node B, and I have to change the fc target in node A.

My question is: If I change this target, how I see the disks?, The server will show them with the same cXtYdZ? I have to do something before and after to change the target?

Thanks a lot of!
Carmen.

[Rita C Workman]

fc target ????

Are you referring to the HBA on your node? Or are you talking about moving from one fiber channel port to another?

[As a SAN Administrator I will simply say-don't touch those fiber connections unless you are the SAN Administrator!! - cause you can seriously create a problem]

Cause doing what you're sounding like your saying may be involving changes in the fabric (i.e. zone) and that is whole different ball game that is on a different team!

But...always make a mapfile of the affected volume groups. Don't worry about the c-t-d- numbers changing, the server can handle that and you can clean up the older drivers later.

Regards,
Rita

[Stephen Doud · Accepted solution]

If paths and device special files change for the LUNs, it's crucial to have LVM map files for each VG, to use with vgimport, which is necessary to update /etc/lvmtab - a file used by LVM to activate volume groups.

Create a map file:
# vgexport -pvs -m .map /dev/

The map file contains the VGID, which can be used with
'vgimport -s' to let LVM do the work of checking LVM metadata on all the disks and import the correct device special files for the VG into /etc/lvmtab.

While you are at it, create a file containing the group minor
numbers (for re-use when re-importing VGs)
# ll /dev/*/group >/etc/lvmconf/groupfiles

After you get the disk hardware path issues sorted out per Rita's recommendations, run ioscan and insf -f to create new device files for LUNs that moved to a new FC adapter hardware path.

Then use vgexport to remove any VGs that now use new device special files:
# vgexport
# mkdir /dev/'
# mknod /dev//group c 54 0xNN000, where NN is derived from /etc/lvmconf/groupfiles (original minor number).

Use the vgimport command to re-import the VG with the new device files:
# vgimport -vs -m .map /dev/

Repeat for all VGs that were moved to a new FC channel/hardware path.

Unfortunately, since the VGs are clustered (activated by Serviceguard), you can only test activation by starting the package, or, if the VG is deactivated on the other nodes, use:
# vgchange -a e
Deactivate using:
# vgchange -a n