Problem Description
-------------------
This efix is for a problem where the VIOS can return an error to the
client for the Test Unit Ready, or Inquiry command.

The fix is for cases where some number of paths on the VIOS are in a
failed state, but there is at least one good path. It does not however
fix a state where path is recovering from a failure, the software has
moved it to a good state but it is not yet fully recovered.  This
problem was encountered on an SVC device where one or more SVC nodes
where rebooted.

The AIX client uses Test Unit Ready to do health check and if it is
active it opens this window of exposure.  This fix is an iterm fix that
in conjuction with turning AIX client health check off.

Health checking is an attribute of the client's physical volume
instance. It can be disabled by issuing the AIX command:

  chdev -l hdiskX -a hcheck_interval=0

The fix is only needed in configurations with redundant VIOS partitions.

This interim fix is included in fix pack 8.1.

Note that with health check interval 0, and this fix an error can still
occur opening the device before any READs, or WRITES, can occur.  


Installation
------------
Download IY91828.epkg.Z in binary format and use the following command
to install the interim fix:

  emgr -e IY91828.epkg.Z