During an upgrade from 6.x to 8.1 we decided to also move the indexes from Lucene to Solr. We ran into quite some troubles, but that is not the question as those are fixed. The "problem" I'm still having is that an index rebuild for sitecore_web_index or sitecore_master_index is taking 5 to 6 hours (on a dedicated dev server). Maybe that is normal for 1 to 1.5M items.. maybe it will go faster on the prod environment. To get it running, we had to put 14GB of memory into the dev server as the initial 7 was not enough. We also had to increase the timeout on the SolrConnection a lot higher than the default (in the Autofac Solr setup).
We do use the index in code to search items based on path, template and or language but have no customizations to these indexes (we have a few custom indexes for those needs).
I was wondering however (this is the actual question) if there is a way to get the indexes rebuild faster. Some config changes to Sitecore or Solr maybe, or .. well anything that might help to reduce the time to rebuild.
On the CD's I do not need the media items in the indexes and apparently I could disable those (which would help - a lot), but what would the side effects be on the CM? Will image fields still work correctly and will I be able to search for a media item? And how do I disable the media items correctly in a default solr config?