This document will outline the steps necessary to reconcile the device paths for a physical tape device that has to be configured on each node within a Networker cluster.

NXCSPLT7

lrwxrwxrwx   1 root     other         50 Jul 22 14:18 0ubn -> ../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0:ubn

lrwxrwxrwx   1 root     other         50 Jul 22 14:18 0mbn -> ../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0:mbn

lrwxrwxrwx   1 root     other         50 Jul 22 14:18 0lbn -> ../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0:lbn

lrwxrwxrwx   1 root     other         50 Jul 22 14:18 0hbn -> ../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0:hbn

lrwxrwxrwx   1 root     other         50 Jul 22 14:18 0cbn ->../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0:cbn

Here we see that /dev/rmt/0cbn list linked to ../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0:cbn

This is where we have the device configured within Networker

NXCSPLT8

lrwxrwxrwx   1 root     other         49 Jul 22 15:02 0un -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:un

lrwxrwxrwx   1 root     other         50 Jul 22 15:02 0ubn -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:ubn

lrwxrwxrwx   1 root     other         49 Jul 22 15:02 0ub -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:ub

lrwxrwxrwx   1 root     other         50 Jul 22 15:02 0mbn -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:mbn

lrwxrwxrwx   1 root     other         49 Jul 22 15:02 0mb -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:mb

lrwxrwxrwx   1 root     other         50 Jul 22 15:02 0lbn -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:lbn

lrwxrwxrwx   1 root     other         49 Jul 22 15:02 0lb -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:lb

lrwxrwxrwx   1 root     other         50 Jul 22 15:02 0hbn -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:hbn

lrwxrwxrwx   1 root     other         49 Jul 22 15:02 0hb -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:hb

lrwxrwxrwx   1 root     other         49 Jul 22 15:02 0cn -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:cn

lrwxrwxrwx   1 root     other         50 Jul 22 15:02 0cbn -> ../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:cbn

lrwxrwxrwx   1 root     other         49 Jul 22 15:02 0cb ->../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0:cb

Here we have the /dev/rmt/0 device for the NXCSPLT8 server.  This is pointing to different physical device than the /dev/rmt/0 entry on the other Networker server.  These entries MUST match when Networker is configured as a cluster.

In order to ensure that the same physical devices are being used, you must know the “devices path” for the same physical device on both servers.

For NXCSPLT7 our “devices path” is:

../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0 and the :cbn (for example) is a control code to the driver to set certain parameters.

For NXCSPLT8 our “devices path” is:

../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0 with the same control code as mentioned previously

*note: although the “device path” in our example match exactly, that may not always be the case.

For our environment we have decided that we want to configure the device on the /dev/rmt/0 device, however we don't want the “extra” device on NXCSPLT8 to just disappear. We can't just arbatraily create a new /dev/rmt/# because there would be no corresponding entries in the /etc/path_to_inst file, and could lead to O/S instability. Therefore we are going swap two devices. First we have to document the current settings for /dev/rmt/0 since we are going to be removing those links.

../../devices/pci@8,700000/pci@3/lpfc@4/st@0,0

Once that is documented, we need to identify what device we are going to be swapping it with. In our case it is /dev/rmt/2. So we need to document those settings as well.

../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0

In addition, we need to list all the device parameters that are available for each.

e.g. un, u, n, mn, mbn, mb, m, ln, lbn, lb, l, hn, hbn, hb, h, cn, cbn, cb, c, bn, b

Keep in mind that not all tape devices will have the same available device settings.

Now remove the existing entries using the proceedure that you are most comfortable with.

e.g. for loop, find command, grep, etc

Once all the devices have been removed, we need to recreate the new links, using the 'ln' command.

e.g. `ln -s ../../devices/pci@8,600000/pci@1/lpfc@4/st@0,0:u 2u`

This command has to be completed for each device, and each device mode to be configured.