This is library for the Go language to enable use of Direct IO under all supported OSes of Go. Direct IO does IO to and from disk without buffering data in the OS. It is useful when you are reading or writing lots of data you don't want to fill the OS cache up with. Instead of using os.OpenFile use directio.OpenFile And when reading or writing blocks, make sure you do them in chunks of directio.BlockSize using memory allocated by directio.AlignedBlock