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Enhancement
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Resolution: Unresolved
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Major
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None
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8.0.0.Alpha2
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None
Cross site replication is configured using JGroups subsystem <relay/> and <remote-site/> elements to define sites and multicast relay routes between sites.
Looking at a site/route configuration as a graph of nodes and edges, xsite only works if this graph is totally connected (i.e. every site has a defined direct route to every other site). This is because <site name> -> <site id> mappings are assigned per node, with no agreement on what is happening at other nodes.
For example, this configuration works:
<relay site="LON">
<remote-site name="NYC" .../>
<remote-site name="SFO" .../>
</relay>
<relay site="NYC">
<remote-site name="LON" .../>
<remote-site name="SFO" .../>
</relay>
<relay site="SFO">
<remote-site name="NYC" .../>
<remote-site name="LON" .../>
</relay>
but this configuration does not:
<relay site="LON">
<remote-site name="NYC" .../>
<remote-site name="SFO" .../>
</relay>
<relay site="NYC">
<remote-site name="LON" .../>
</relay>
<relay site="SFO">
<remote-site name="LON" .../>
</relay>