Gecko: A Contention-Oblivious Design for Cloud Storage

Disk contention is a fact of life in modern data centers, with multiple applications sharing the storage resources of a single physical machine. Log-structured storage designs are ideally suited for such high-contention settings, but historically have suffered from performance problems due to cleaning overheads. In this paper, we introduce Gecko, a novel design for storage arrays where a single log structure is distributed across a chain of drives, physically separating the tail of the log (where writes occur) from its body1. This design provides the benefits of logging – fast, sequential writes for any number of contending applications – while eliminating the disruptive effect of log cleaning activity on application I/O.