Lowering K-Safety to Enable Node Removal

A database with a K-safety level of 1 requires at least three nodes to operate, and a database with a K-Safety level 2 requires at least 5 nodes to operate. To remove a node from a cluster that is at the minimum number of nodes for its database's K-safety level, first lower the K-safety level with MARK_DESIGN_KSAFE.

Lowering the K-safety level of a database to 0 eliminates Vertica's fault tolerance features. If you must reduce K-safety to 0, first back up the database.

To lower the K-safety level of the database:

  1. Connect to the database with Administration Tools or vsql.
  2. Call the function MARK_DESIGN_KSAFE:

    SELECT MARK_DESIGN_KSAFE(n);

    where n is the new K-safety level for the database.