Function1

The Aqualogic portal has a neat feature called the Parallel Portal Engine, or PPE. This allows you to set up multiple remote servers (for custom code, or even clustering some of the Aqualogic products, like Collaboration Server) and get the portal to distribute requests to all of them.

The way this works is you start by setting up multiple IP addresses for a single host name in your Domain Name Server (DNS). You then use that host name for a remote service you want to load balance, and the portal does the rest: load balancing requests between the servers, ensuring session affinity, and handling failover when a server becomes unresponsive.

This is all great, but what if you’re in an environment where editing the DNS is undesirable or impractical? There’s a way to configure the 6.x ALUI portal to use this feature without the help of DNS, but documentation is so scare I thought it was worth a mention here. In fact, the only mention of it I could find was in the appendix of the Publisher Installation Guide, but I know this mechanism has also been used in environments where Collaboration Server was clustered, and it will no doubt work with custom portlets as well.

Just edit the %PTHOME%\settings\common\serverconfig.xml file and add the following lines to the <component name=”openhttp”> section, where #.#.#.# represents the multiple IP addresses you want to use for the host name SERVERNAME:

  <!– LoadBalancing –>

<setting name=”openhttp:LoadBalancedHost0″>

<value xsi:type=”xsd:string”>SERVERNAME</value>

</setting>

<setting name=”openhttp:LoadBalancedIPs0″>

<value xsi:type=”xsd:string”>#.#.#.#;#.#.#.#</value>

</setting>

<setting name=”openhttp:FailuresTimeToClear”>

<value xsi:type=”xsd:integer”>30</value>

</setting>

10/31/07 Update: According to the release notes for the ALUI 6.1 MP1 Patch 1, there was a problem with this setting in prior versions of 6.1:

The openhttp:LoadBalancedIPs setting is not properly processed. (Issue #55532)

So, if you’ve tested this trick out and it didn’t work; give it another go after you install MP1 Patch 1!