Limits for Search have changed significantly as the feature has been updatedRead full story on technet.microsoft.com
#SharePoint2013 Search limits have increased significantly since October CU (kb 2825672). You can have 64 search components per SSA, crawl components are aligned with this boundaries. 250M items can be indexed per indexer. Crawl log entries are unlimited and you can have 15 Crawl DB per SSA. 4 index components can run on one single server.