Unified replication mechanism for fault-tolerance of state

For a first controller instance of a network control system that manages a set of forwarding elements implementing logical datapath sets, a machine-readable medium storing a program executable by at least one processing unit of the first controller instance, the program comprising sets of instructions for:

• receiving, at a first table, a set of input records that indicate changes to a forwarding state of the network control system, wherein each input record triggers a plurality of modifications to a plurality of tables for storing a plurality of tuples used for defining the forwarding state;
• for each input record:
• performing the plurality of modifications to the plurality of tables;
• and
• logging the modifications for each table in the plurality of tables;
• and
• based on resources of the first controller instance, pruning the logged modifications for a subset of the tables from a log;
• and
• storing a snapshot for each table of the plurality of tables that is not in the subset of tables.

A method for implementing logical datapath sets and a machine-readable medium storing a program executable by at least one processing unit of the first controller instance, the method comprising:

• receiving, at a first table, a set of input records that indicate changes to a forwarding state of the network control system, wherein each input record triggers a plurality of modifications to a plurality of tables for storing a plurality of tuples used for defining the forwarding state;
• for each input record:
• performing the plurality of modifications to the plurality of tables;
• and
• logging the modifications for each table in the plurality of tables;
• and
• based on resources of the first controller instance, pruning the logged modifications for a subset of the tables from a log;
• and
• storing a snapshot for each table of the plurality of tables that is not in the subset of tables.