Seven case studies where Cassandra performance fell short` Cassandra's open-source licensing makes it an attractive option for companies seeking cost-effective technical solutions; however, its performance issues can lead to higher operational expenses due to challenges in monitoring inefficiencies and scalability concerns. In these seven case studies, companies such as TransUnion TruAudience, LexisNexis Risk Solutions, The Trade Desk, Adform, Wayfair, InMobi, and a multinational medical device manufacturer struggled with Cassandra's performance issues, including large data latencies, frequent database incidents, downtime, and scalability concerns. These challenges led to increased operational efforts, such as tuning the Java virtual machine, diverting resources from higher-value projects, and implementing workarounds, ultimately resulting in significant cost savings when switching to alternative data solutions like Aerospike.