Installation guide

96107 Fourth Edition 19
StorageTek Proprietary
AIX Host Installation/Upgrade Procedures
autorecovery process. It is best to experiment with the advanced
administration and display capabilities to understand how it all interacts. Once
you understand how all of the commands work and interact, create the
appropriate shell script that contains the DPFutil commands that administer/
display the primary paths for this custom installation.
Warning: These administered changes for primary paths will be lost on a
upgrade of the Cambex DPF Failover driver, so they should be
scripted (via DPFutil commands, not SMIT) for your installation and
saved to be used in the event of a Cambex DPF Failover driver
upgrade.
Testing Failover
The following sections describe testing the various path failover scenerios.
In these test procedure examples, a path failure was caused by removing the
fibre cable from controller A while doing I/O to all four LUNs. I/O should
resume after a few seconds. It is important to note that a LUN will not failover
until I/O is attempted to it, thus triggering a failure of the current path. The
failure of the standby path is detected by the background DPF autorecovery
process. This will detect the failure of the backup path within a few minutes.
Display the path status using the dpfutil listall command or Smit
Devices >> Cambex Fibre Channel Adapter >> Change Cambex
Dynamic Path Management / Show Device Status.
Normal Condition
Example outputs before cable was pulled:
/usr/lpp/cbxdpf/dpfutil listall
# Device Active Standby
hdisk1 cbx0 (fscsi0 0,0) cbx4 (fscsi1 0,0)
hdisk2 cbx1 (fscsi0 0,1) cbx5 (fscsi1 0,1)
hdisk3 cbx6 (fscsi1 0,2) cbx2 (fscsi0 0,2)
hdisk4 cbx7 (fscsi1 0,3) cbx3 (fscsi0 0,3)
Single Path FAILOVER Condition
Disconnect the cable from controller A with active I/O to all LUNs. After a few
minutes the dpfutil listall command displays the following.
# Device Active Standby
hdisk1 cbx4 (fscsi1 0,0) Fcbx0 (fscsi0 0,0)
hdisk2 cbx5 (fscsi1 0,1) Fcbx1 (fscsi0 0,1)
hdisk3 cbx6 (fscsi1 0,2) Fcbx2 (fscsi0 0,2)
hdisk4 cbx7 (fscsi1 0,3) Fcbx3 (fscsi0 0,3)
When the “single path bad” condition has been detected for a LUN, a single
error message is generated in the error log as follows.