Doug, (old email) My initial guesses would be: * GC * Lucene segment merging happening on multiple indices during the same time (check IO before/after/during high load) * too frequent auto-commit (though this sounds least likely, as if this were the cause you'd see high load all the time)
Maybe you already figured it out? What was it? Otis -- Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch ----- Original Message ---- > From: Doug Steigerwald <[EMAIL PROTECTED]> > To: solr-user@lucene.apache.org > Sent: Wednesday, July 2, 2008 12:54:04 PM > Subject: High load when updating many cores > > We're experiencing some high load on our Solr master server. It > currently has 30 cores and processes over 3 million updates per day. > During most of the day the load on the master is low (0.5 to 2), but > sometimes we get spikes in excess of 12 for hours at a time. > > The only reason I can figure why this is happening because we're > updating almost all of our cores during those times. Usually during > the day our sites update pretty randomly, but it seems like many of > them send updates at the same time. > > Over a 3 hour period where the load was ~12 we had only 156k updates. > Usually a pretty light load when updating a single core through just a > few producers. It seems as though we're just getting updates from > nearly all of our 30 cores at once, and something in the background is > slowing down. > > Here's some stats about our setup. > > 4x3.2GHz Xeon. 8GB RAM. RHEL 5.1. 4GB max heap size for Solr. Our > build is a trunk build from January (using Lucene 2.3.0). Java > 1.6.0_03-b05 (64bit). > > Using Jetty started as: 'java -server -Xms1024m -Xmx4096m -jar > start.jar' > > We never query the master, but we do have caching enabled (same > configs on master and slave). autowarmCount is set to 0 for each core > (they all use the same configs). We autocommit every 5 seconds. > > Any ideas what might cause the load to spike? Could it be our caching > even though we have autowarmCount set to 0? Could it be that Solr is > trying to merge a lot of indexes at once? > > Maybe some garbage collection stuff? > > Thanks. > Doug
