recoverUnknown (Hbck2)

Schedules a ServerCrashProcedure (SCP) for RegionServers that are reported as unknown in the cluster state.

Command Syntax

Description

Use this command when the HBase Master has lost track of one or more RegionServers and they appear as unknown in the cluster status. Running recoverUnknown schedules an SCP for each unknown server so HBase can:

• Re-establish control of the affected RegionServers, and

• Recover or reassign regions that were previously hosted on them.

This command is supported in the following HBase versions:

• 2.2.7

• 2.3.5

• 2.4.3

• 2.5.0 and newer

Return Value

• The command returns one or more PIDs for the newly created SCPs.

• If no procedures are created, it returns -1.

• If no SCPs are initiated, consult the Master logs for specific reasons.

Example