Server failure recovery

摘要

A metadata server configured to maintain storage assignment mappings in non-persistent storage is described herein. The tract storage assignment mappings associate servers with storage assignments, the storage assignments representing the data stored on the servers. Responsive to a failure, the metadata server receives the storage assignments from the servers and rebuilds the storage assignment mappings from the storage assignments. The metadata server is also configured to enable clients to operate during a recovery process for a failed server by providing the storage assignment mappings to the clients during the recovery process. Also during the recovery process, the replacement server for the failed server conditionally overwrites stored data with other data received from other servers as part of the recovery process. The replacement server conditionally overwrites based on version information associated with the data and version information associated with the other data, the version information being associated with one or more versions of the storage assignment mappings.

主权项

1. A metadata server comprising:
a processor; and a recovery module configured to be executed by the processor for implementation of a recovery process associated with a failure of a server of a system, the recovery module to:
provide a new recovery plan to one or more replacement servers, the new recovery plan proposing the one or more replacement servers for replacement of the failed server;update previous storage assignment mappings associated with a previous recovery plan based on the new recovery plan such that new storage assignment mappings specify the one or more replacement servers as being associated with storage assignments of the failed server;transmit the new storage assignment mappings to one or more clients of the system during the recovery process to enable the one or more clients to operate during the recovery process;manage, during the recovery process, writing of a first instance of the data by servers of the system to the one or more replacement servers of the system, the first instance of the data being stored by the servers and the failed server and the first instance of the data being associated with a first version identifier;manage, during the recovery process, writing of a second instance of at least a portion of the data by the one or more clients to the one or more replacement servers of the system, the second instance of at least the portion of the data being associated with a second version identifier indicating that the second instance of at least the portion of the data is newer than corresponding data in the first instance of the data andstore, in the one or more replacement servers and based at least in part the second version identifier, the second instance of at least the portion of the data instead of the corresponding data in the first instance of the data.