Burp is a network backup and restore program. It attempts to reduce network
traffic and the amount of space that is used by each backup. There are two
independent backup protocols to choose from:
- Protocol 1: Optionally uses librsync.
  Available in all burp versions and is stable.
- Protocol 2: Uses variable length chunking for inline deduplication, and
  sparse indexing on the server side.
  Available from burp version 2.0.x, but is experimental and should not be used
  in production.