gc

Documentation

Overview

Package gc contains the functions needed to run garbage collection.

Package gc/bloomfilter creates retain instructions. These are compressed lists of piece id's that storage nodes must keep. It uploads those to a bucket.

gc/bloomfilter is designed to run on a satellite pointed to a backup snapshot of the metainfo database. It should not be run on a live satellite: due to the features move and copy object, pieces can move to different segments in the segments table during the iteration of that table. Because of that it is not guaranteed that all piece ids are in the bloom filter if the segments table is live.

Package gc/sender reads the retain instructions from the bucket and sends them to the storage nodes. It is intended to run on a satellite connected to the live database.

Should we ever delete all segments from the satellite's metainfo, then no bloom filters will be generated, because GC only considers NodeID's inside the segments table. There is also an explicit check that stops sending out an empty bloom filter to a storage node.

See storj/docs/blueprints/garbage-collection.md for more info.