Percona Server tree with support of Fusion-io atomic writes and DirectFS

Not so long ago Fusion-io announced an SDK which provides direct API access to Fusion ioMemory(tm) in addition to providing a native filesystem (directFS) with a goal to avoid overhead from kernel and regular Linux filesystems: ext4 and xfs. This requires a support from application, it should use special calls for IO. With help from Fusion-io, we provide source code of Percona Server which uses direct API access. The main idea that with this functionality you can disable “innodb-doublewrite”, retain ACID compliance by using atomic writes, and in IO intensive workloads gain an additional 30-50% in throughput when compared to workloads on the same ioMemory™ device using an unmodified Percona Server. Further benchmarking results on latency variability reduction expected soon.