When file-cache/sendfile is set to true, Web Server uses the operating system sendfile call to service large static files from the file cache. The performance of serving such files from the file cache can be improved by limiting the number of bytes sent by a single sendfile call. Using a non zero value for file-cache/sendfile-size will send the file in chunks, where the chunk size is at the most the size of sendfile-size.
While serving large files, for example, movie files, consider tuning the file-cache/sendfile-size. A sendfile-size of 1MB can provide improved performance compared to the default sendfile-size of zero. You can set the sendfile-size in Admin Console by editing Sendfile Size field on the configuration's Performance tab ⇒ Cache tab, under File Cache. In the command-line interface, use wadm set-file-cache-prop command's sendfile-size property.