Distributed Name Service (DNS) Management Programming Manual

Event Management Strategies
Event Messages
6–6 46958 Tandem Computers Incorporated
Event-Management
Strategies
This subsection presents some guidelines for managing DNS based on the event
messages that DNS generates.
Filtering DNS Event
Messages
Those DNS messages that have ZDNS-TKN-SEVERITY = ZDNS-VAL-SEVERITY-
STATUS (0) represent event messages that are expected in the normal functioning of
DNS. Filters should normally select only those event messages with ZDNS-TKN-
SEVERITY > 0. The Event Management Service (EMS) Manual describes how to create
filters.
Event Messages Caused by
CPU and Network Failures
Some DNS event messages occur as a result of the receipt of CPU DOWN or
MONITORNET system messages. These are:
ZDNS-EVT-TASK-ABORT (7)
ZDNS-EVT-BACKUP-DELETED (13)
ZDNS-EVT-SYSTEM-DOWN (18)
ZDNS-EVT-EXP-FAIL (30)
Since these failures are reported by Guardian 90 or Expand, you may wish to filter
these DNS event messages.
ALLOWIMPORTS Attribute The ALLOWIMPORTS attribute is implemented to prevent the generation of ZDNS-
EVT-TYPE-ERROR when adding a new DNS system to a network or during reload of
the database on a network node.
When DNS is started for the first time after an INITIALIZE DNS command has been
executed, the DNS database is empty; in particular, no type names (SSTYPE,
ALIASTYPE, or COMPOSITETYPE) are defined. If the system just initialized is a
member of domains on other network nodes, those nodes may attempt to export
names to that system before the type names have been loaded. This could lead to a
host of ZDNS-EVT-TYPE-ERROR messages on the initialized node, and on other
nodes in the network.
By initially defining ALLOWIMPORTS = OFF (the default value), this problem may be
avoided. Should remote systems attempt to export names to a node with
ALLOWIMPORTS = OFF, the export is rejected and a ZDNS-EVT-IMPORT-
REJECTED message is generated.
The recommended method of initializing DNS on a system is as follows:
SET ALLOWIMPORTS OFF
INITIALIZE DNS
START DNS == (A)
load type name s
STOP DNS, WAIT ON == (B)
ALTER DNS, ALLOWIMPORTS ON
START DNS