Overview of Fault Detection and Recovery

If ftsprobe cannot connect to a segment, it marks the segment as “down” in the Greenplum Database system catalog. The segment remains nonoperational until an administrator initiates the recovery process.

To recover failed segments, an administrator runs the recovery utility. This utility locates the failed segments, verifies they are valid, and compares the transactional state with the currently active segment to determine changes made while the segment was offline. gprecoverseg synchronizes the changed database files with the active segment and brings the segment back online. Administrators perform the recovery while Greenplum Database is up and running.

See Detecting a Failed Segment for a more detailed description of the fault detection and recovery process and configuration options.