SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Managing an SQL/MX Distributed Database
HP NonStop SQL/MX Installation and Management Guide—523723-004
13-16
Maintaining Local Autonomy in a Network
revised configuration, node \B becomes more of a single point of failure for the
distributed database.
Clearly, the configuration described in Table 13-4 has less local autonomy than the
configuration described in Table 13-3 on page 13-14. Because node \B represents a
single point of failure, this configuration is not advisable in a geographically distributed
environment. However, in a locally distributed environment where all three nodes are in
the same computer room and a reliable high-speed network interconnect is used, the
risks of this configuration are reduced.
Depending on the interrelationships between the involved catalogs, you might want to
implement the configuration described in Table 13-5
on page 13-17. In this
configuration, CAT_1 is created on node \A and CAT_2 on node \B, so their respective
object metadata remain on these two nodes.
Table 13-4. Consequences of Network Node Loss, Reconfiguration 1
Node
CAT_1 and
CAT_2
User Data
Present?
CAT_1 and
CAT_2
Metadata
Present?
CAT_1 and
CAT_2
Applications
Present?
Consequences of Losing
This Node on the Other
Nodes
\A Yes No No The same consequences
occur as were identified in the
node \A row in Table 13-3
on
page 13-14.
\B Yes Yes Yes The same consequences
occur as were identified in the
node \B row in Table 13-3
on
page 13-14. In addition, none
of the applications that contain
queries to CAT_1 or CAT_2
can be executed.
\C Yes No No The same consequences
occur as were identified in the
node \C row in Table 13-3
on
page 13-14