Malfunction in the BlockPlacementPolicyRackFaultTolerant when handling racks with limited nodes, leading to the failure of allocating the necessary data nodes despite adequate resources within the cluster. The issue stems from the policy's restriction on the maximum nodes per rack, hindering allocation attempts in racks with fewer nodes. As a result, the system encounters data write failures and placement inconsistencies.

The fix involves modifying the placement logic to remove this restriction, enabling a fallback strategy for allocating nodes in such scenarios. This enhancement ensures the BlockPlacementPolicyRackFaultTolerant can effectively handle uneven rack configurations, bolstering the reliability and adaptability of Hadoop's block placement mechanism, particularly in clusters with diverse rack distributions.