2. Neglecting high availability and disaster recovery

Proprietary database vendors often present their high availability and disaster recovery solutions as turnkey systems that "just work," hiding the reality of their limitations. Their marketing materials promise "enterprise-grade resilience" and "guaranteed uptime," but rarely specify exactly what these claims mean in practice. They market simplified management interfaces and automated failover as justification for premium pricing, but these solutions often impose rigid architectures that don't adapt to your specific business needs.

It's critical to scrutinize what vendors actually deliver versus what they promise, as the gap between these can be substantial. When real disasters strike—whether hardware failure, network issues, or data corruption—the limitations of these inflexible proprietary systems become painfully apparent, resulting in extended downtime, data loss, and damaged customer trust.

Consider this: A financial services company relied on a proprietary database vendor's "guaranteed" high availability solution, promising 99.99% uptime. During end-of-quarter processing, the primary database server failed. An unexpected edge case caused the failover to stall, turning what should have been a 30-second transition into a four-hour outage, costing millions. When they sought accountability, the vendor simply pointed to the fine print in the SLA that excluded this specific scenario. We've seen how these situations unfold, highlighting why thoroughness in availability testing matters.