As far as I know Slony is also a master/slave replication, moreover it is asynchronously, so if the master site server fails the newest pieces of data can be lost.<br><br>I can describe the problem in an other way: can a PostgresSQL database behind PgPool-II be modified by other applications directly? If it can, then tehh other application can be another PgPool-II. In this case I suppose the developers have to take care about distinct sets of identifiers for the sites and special recovery scripts/actions for the case of online recovery...<br>
<br>Csaba<br><br><div class="gmail_quote">On 24 October 2012 17:11, Wolf Schwurack <span dir="ltr"><<a href="mailto:wolf@uen.org" target="_blank">wolf@uen.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">If you are looking for pgpool on multiple host this is the way to go. If one of the pgpool server fails then the other will take over. This in the only method
if you want multiple pgpool servers. You don’t have to use master/slave. You could set it up using slony if you like
<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Wolf<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Csaba Simon [mailto:<a href="mailto:simocsab@gmail.com" target="_blank">simocsab@gmail.com</a>]
<br>
<b>Sent:</b> Wednesday, October 24, 2012 9:01 AM<br>
<b>To:</b> Wolf Schwurack<br>
<b>Cc:</b> <a href="mailto:pgpool-general@pgpool.net" target="_blank">pgpool-general@pgpool.net</a><br>
<b>Subject:</b> Re: [pgpool-general: 1107] Using PgPool-II on multiple hosts<u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hi,<br>
<br>
Thanks for your quick answer, but this part of the documentation is about a master-slave server pair with a standby server. In contrast with it our architecture would have two PgPool-II nodes on different company sites and they would serve 2-2 databases nodes
(2 PostgresSQL db servers per site), all of the nodes should be active and synchronized while working normally.<br>
<br>
Is not it possible just use two individual PgPool-II servers for the 4 databases?<br>
<br>
Csaba<u></u><u></u></p>
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<p class="MsoNormal">On 24 October 2012 15:29, Wolf Schwurack <<a href="mailto:wolf@uen.org" target="_blank">wolf@uen.org</a>> wrote:<u></u><u></u></p>
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<p><a href="http://www.pgpool.net/pgpool-web/contrib_docs/watchdog_master_slave/en.html" target="_blank">http://www.pgpool.net/pgpool-web/contrib_docs/watchdog_master_slave/en.html</a><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Take a look at this doc</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Wolf</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><u></u><u></u></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
<a href="mailto:pgpool-general-bounces@pgpool.net" target="_blank">pgpool-general-bounces@pgpool.net</a> [mailto:<a href="mailto:pgpool-general-bounces@pgpool.net" target="_blank">pgpool-general-bounces@pgpool.net</a>]
<b>On Behalf Of </b>Csaba Simon<br>
<b>Sent:</b> Wednesday, October 24, 2012 6:24 AM<br>
<b>To:</b> <a href="mailto:pgpool-general@pgpool.net" target="_blank">pgpool-general@pgpool.net</a><br>
<b>Subject:</b> [pgpool-general: 1107] Using PgPool-II on multiple hosts</span><u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hi,<br>
<br>
Can I use PgPool-II on multiple hosts avoiding my single PgPool-II instance to be the single point of failure in the architecture?
<br>
<br>
For example I would like to use four active PostgresSql database nodes with two active PgPool-II nodes in replication mode. Is this a usual and usable architecture?<br clear="all">
<br>
Csaba<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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