Echelon LNS - Manual (Page 273)

LNS Programmer's Guide 259
• The recovery process has no way of determining what network variables
are hubs, and what network variables are targets, in the connections on
the recovered network. These relationships are arbitrarily assigned.
Because the hub/target relationships may change, the recovery may not
restore the proper connection descriptions to the connections on the
recovered network. If the recovery is unable to determine the correct
connection description for a connection, it uses the default connection
description.
• In many cases, information stored in the network database will be lost,
and LNS will make its best guess based on the information it does
recover on how to fill in the lost information during the network recovery.
This includes most properties of the System object.
• If LNS cannot communicate with a device, the device will not be
recovered. This will create inconsistencies in any connections that the
device was part of. LNS will recover those connections to the extent
possible, leaving out the missing device. LNS takes the following actions
when this sort of inconsistency is detected:
• If a bound network variable has no associated source or target, it is
marked as unbound. No address is associated with this network variable.
The connection is lost.
• If a bound dedicated message tag has no targets, its address table entry is
marked as empty. The connection is lost.
• Any address table entries that are not associated with a network variable
or message tag (source or target) are marked as empty. A lost source or a
lost target may create this situation. Group use counts are updated as
necessary, and group IDs are freed as necessary.
• If the configuration of a device in the recovered network is inconsistent,
then LNS will not recover its connections properly, possibly effecting
other connections in ways that were not intended.
• The configuration of your Network Service Device will be not be recovered
during this process, as the configuration of the device, including the
network variable configuration, network variable selector values, and
most of the Network Service Device’s address table entries, are stored on
the PC containing the network database. As a result, monitor sets on the
Network Service Device, and all connections involving the Network
Service Device, will not be recovered.
• If you have modified the attributes of the network image of any of the
devices in your network outside of LNS, including the channel ID of any
of the devices, the LNS Object Server may be unable locate that device on
the network during recovery. This may cause the network recovery to fail.
• Any information specific to LNS but without correspondence on the
physical network cannot be recovered. This includes user-defined data
(Extension objects), subsystem assignment, and registration
information for plug-in software (ComponentApp objects).
For all of these reasons, you should use database backup as the primary means of
preventing database loss. In addition, you should examine the recovered database to
ensure its stability and consistency after performing a network recovery.