参考链接：
https://www.percona.com/doc/percona-server/5.5/performance/atomic_fio.html
http://www.ywnds.com/?p=8334
atomic write:
DirectFS filesystem on Fusion-io devices supports atomic writes. Atomic writes can be used instead of InnoDBdoublewrite buffer to guarantee that the InnoDB data pages will be written to disk entirely or not at all. When atomic writes are enabled the device will take care of protecting the data against partial writes. In case the doublewrite buffer is enabled it will be disabled automatically. This will improve the write performance, because data doesn’t need to be written twice anymore, and make the recovery simpler.