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<P><FONT SIZE=2>I'm looking at Spread to implement a data replication scenario, but the documentation is ambiguous enough that I can't tell is Spread is suitable or not.</FONT></P>
<P><FONT SIZE=2>The scenario has a central shared database with (say) 30 client sites sharing the data. Each of these client sites also has a site-specific database that is shared with the central site. Each of the 31 sites can update its own copy of the shared database and site-specific database, and each night, changes are copied to the central site. (Ignore possible conflicts for the purposes of this explanation.)</FONT></P>
<P><FONT SIZE=2>Spread would appear to be useful in that the client sites could fetch their copy of the shared database changes in a sequence of reliably delivered messages, and send their copy of the site-specific database changes likewise.</FONT></P>
<P><FONT SIZE=2>My initial experiment with Spread doesn't look promising. I set up a Spread daemon with two clients (spuser) in the same group, and sent messages between clients using spuser's default SAFE_MESS. If a receiving client dies, then further messages sent to that group are lost, which doesn't seem very safe. Membership of a group appears to require the client being connected, and the Spread daemon doesn't store the messages until the client comes online.</FONT></P>
<P><FONT SIZE=2>The documentation makes it hard to figure out what is meant by "reliable". It appears that my concept of reliable (JMS persistent messages, for instance) isn't the same as Spread's. There's nothing wrong with that, but I'm not sure what spread's definition of reliable is.</FONT></P>
<P><FONT SIZE=2>However, it appears that sending a list of changes via Spread, with the currently off-line clients fetching them whenever they are able, is not suited to the spread paradigm.</FONT></P>
<P><FONT SIZE=2>If the client sites connect to the central site and ask for updates since the last time they connected, I'm not sure what extra benefit Spread provides over and above a simple TCP connection between sites. (A slightly provocative statement, but I'm trying to get educated. :-)</FONT></P>
<P><FONT SIZE=2>Comments? Thanks.</FONT>
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<P><FONT SIZE=2>PJDM</FONT>
<BR><FONT SIZE=2>-- </FONT>
<BR><FONT SIZE=2>Peter Mayne</FONT>
<BR><FONT SIZE=2>Technology Consultant</FONT>
<BR><FONT SIZE=2>Spherion Technology Solutions</FONT>
<BR><FONT SIZE=2>Level 1, 243 Northbourne Avenue, Lyneham, ACT, 2602</FONT>
<BR><FONT SIZE=2>T: 61 2 62689727 F: 61 2 62689777</FONT>
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