As of FairCom DB Version 9.0, COMPATIBILITY LOG_WRITETHRU is synonymous on both Windows and Unix platforms.
On Unix systems, instructs the FairCom DB Server to open its transaction logs in synchronous write (direct I/O on Solaris) mode. In this mode, writes to the transaction logs go directly to disk (or disk cache), avoiding the file system cache, so the server is able to avoid the overhead of first writing to the file system cache and then flushing the file system cache buffers to disk. This keyword also causes flushed writes for data and index files to use direct I/O. Using this keyword enhances performance of transaction log writes.