proftpd-mod-fsync - 0.3-3+b1 main

The mod_fsync module attempts to prevent such bottlenecks by forcibly
flushing to disk the buffers used for files open for writing after a
certain number of bytes have been written (for example, after 128 KB
has been written to a file). This prevents the buffer cache from being
dominated by data from files being written, freeing up space for data
for files being read.