QLogic VNIC Dynamic Update Daemon :-

This tool is started and stopped as part of the QLogic VNIC service
and provides the following features:

1. Dynamic update of disconnected interfaces (which have been configured
WITHOUT using the DGID option in the configuration file) :

At the start up of VNIC driver, if the HCA port through which a particular VNIC
interface path (primary or secondary) connects to target is down or the
EVIC/VEx IOC is not available then all the required parameters (DGID etc) for connecting
with the EVIC/VEx cannot be determined. Hence the corresponding VNIC interface
path is not available at the start of the VNIC service. This daemon constantly
monitors the configured VNIC interfaces to check if any of them are disconnected.
If any of the interfaces are disconnected, it scans for available EVIC/VEx targets using
"ib_qlgc_vnic_query" tool. When daemon sees that for a given path of a VNIC interface,
the configured EVIC/VEx IOC has become available, it dynamically updates the
VNIC kernel driver with the required information to establish connection for
that path of the interface. In this way, the interface gets connected with
the configured EVIC/VEx whenever it becomes available without any manual
intervention.

2. Hot Swap support :

Hot swap is an operation in which an existing EVIC/VEx is replaced by another
EVIC/VEx (in the same slot of the switch chassis as the older one). In such a
case, the current connection for the corresponding VNIC interface will have to
be re-established. The daemon detects this hot swap case and re-establishes
the connection automatically. To make use of this feature of the daemon, it is
recommended that IOCSTRING be used in the configuration file to configure the
VNIC interfaces.

This is because, after a hot swap though all other parameters like DGID, IOCGUID etc
of the EVIC/VEx change, the IOCSTRING remains the same. Thus the daemon monitors
for changes in IOCGUID and DGID of disconnected interfaces based on the IOCSTRING.
If these values have changed it updates the kernel driver so that the VNIC
interface can start using the new EVIC/VEx.

If in addition to IOCSTRING, DGID and IOCGUID have been used to configure
a VNIC interface, then on a hotswap the daemon will update the parameters as required.
But to have that VNIC interface available immediately on the next restart of the
QLogic VNIC service, please make sure to update the configuration file with the
new DGID and IOCGUID values. Otherwise, the creation of such interfaces will be
delayed till the daemon runs and updates the parameters.

