syncfs On Linux syncfs() may be specified for some configuration parameters (e.g., ), server applications (e.g., pg_upgrade), and client applications (e.g., pg_basebackup) that involve synchronizing many files to disk. syncfs() is advantageous in many cases, but there are some trade-offs to keep in mind. Since syncfs() instructs the operating system to synchronize a whole file system, it typically requires many fewer system calls than using fsync() to synchronize each file one by one. Therefore, using syncfs() may be a lot faster than using fsync(). However, it may be slower if a file system is shared by other applications that modify a lot of files, since those files will also be written to disk. Furthermore, on versions of Linux before 5.8, I/O errors encountered while writing data to disk may not be reported to the calling program, and relevant error messages may appear only in kernel logs.