mbuffer (a tool for buffering data streams)

mbuffer has a large set of unique features:
  - direct support for TCP based network targets (IPv4 and IPv6)
  - ability to send to multiple targets in parallel
  - support for multiple volumes
  - I/O rate limitation
  - high/low watermark based restart criteria
  - configurable buffer size
  - on the fly MD5 hash calculation

It is especially useful, if you are writing backups to fast tape drives
or libraries. Those drives tend to stop and rewind if they have a buffer
underrun. This so called tape screwing reduces the lifetime of the
motors.

mbuffer can prevent buffer underruns, if used correctly and speed up
the whole backup process. Please read the man page for details, how to
use it.