The Smoke and Mirrors File System (SMFS) mirrors files at geographically remote datacenter locations with negligible impact on file system performance at the primary site, and minimal degradation as a function of link latency. It accomplishes this goal using wide-area links that run at extremely high speeds, but have long round-trip-time latencies--a combination of properties that poses problems for traditional mirroring solutions. In addition to its raw speed, SMFS maintains good synchronization: should the primary site become completely unavailable, the system minimizes loss of work, even for applications that simultaneously update groups of files. We present the SMFS design, then evaluate the system on Emulab and the Cornell National Lambda Rail (NLR) Ring testbed. Intended applications include wide-area file sharing and remote backup for disaster recovery.