[VuFind-Tech] high availability question

[Tuan N. <tu...@yo...>]

Hi everyone,

I am pondering the idea of have of modifying the sys/Solr.php and sys/ConnectionManager.php to allow for a list of SOLR servers to try upon failure or to switch to a different solr host if the response time is not adequate.

Has anyone done this? If so, would you please share your experience and/or code.

We currently have 2 solr instances sitting on 2 servers. We have apache mod_proxy sitting in front and pass connections to the 2 back-end solr instances. At this time we have one server set up as hot failover. This has been working quite well. However, it requires setting up apache to direct requests. One of the problem that we have been seeing is that when the main SOLR instance is busy, the requests keep piling on and failover does not kick in until that instance is dead. Ideally, I would like to have the failover happens as soon as the request takes for than 2 or 3 seconds, thus giving the users an adequate response time as well as relieving the stress on the other server.

I am thinking of implementing this functionality inside of sys/Solr.php, but I am hoping I don't have to.

Thanks,
Tuan