Lustre 1.6 Operations Manual

18.2 Types of Failure
Different types of failure can cause Lustre to enter recovery mode:
Client (compute node) failure
■ MDS failure (and failover)
■ OST failure
■ Transient network partition
■ Network failure
■ Disk state loss
■ Down node
■ Disk state of multiple, out-of-sync systems
Currently, all failure and recovery operations are based on the notion of connection
failure. All imports or exports associated with a given connection are considered as
failed if any of them do.
18.2.1 Client Failure
Lustre supports for recovery from client failure based on the revocation of locks and
other resources, so surviving clients can continue their work uninterrupted. If a
client fails to timely respond to a blocking AST from the Distributed Lock Manager
or a bulk data operation times out, the system removes the client from the cluster.
This action allows other clients to acquire locks blocked by the dead client, and it
also frees resources (such as file handles and export data) associated with the client.
This scenario can be caused by a client node system failure or a network partition.
18-2 Lustre 1.6 Operations Manual • September 2008