On Thu, 2014-10-09 at 15:06 +0200, Yannick wrote: > I created a group of 2 Solr servers with a load-balancer in front > (Haproxy). I have a batch client that sends requests (read-only) > continuously to the load-balancer. The problem is: the performance is > slower with 2 servers than it is with a single server (still via the > load-balancer, with the second server down, so it's not the > load-balancer itself causing the slowdown).
(speculating a lot here:) Is another job updating the indexes while you are batch-searching? If so, the slowdown could be explained by the servers disk caches being flushed by the indexing job. When a request arrives some cache is reclaimed, but is will be a battle between the update and the search jobs. With more machines, there will be fewer request/machine, so the search-cache has a lower chance of being used again before it is reclaimed by the updater. Still, worse performance for 2 machines sounds pretty bad. - Toke Eskildsen, State and University Library, Denmark
