Everyone wants their Elasticsearch cluster to index and search faster, but optimizing both and finding the balance between the two can be tricky. At Kenna Security, we use Elasticsearch to store over 3 billion vulnerabilities for our clients. All that data needs to be quickly accessible so clients can assess their cyber security risk. At the same time the data is constantly changing. On average, we update 200+ million documents a day which means indexing speed is also a top priority. In the early days our cluster could barely keep up. Nodes would fall over constantly, indexing queues would get backed up for days, and searches timed out about 50% of the time. Fixing all of these issues did not happen overnight. However, with a lot of testing, tweaking, and a few “OH crap!” moments we were able to build a stable, 21 node cluster that now meets all of our indexing and searching demands. In this talk I will share the insights we gained and the strategies we used to scale our cluster and hopefully that advice will save others some time and frustration as they grow their own.