Online data consistency checking in a network storage system with optional committal of remedial changes

摘要

A network storage server includes a tool for detecting and fixing errors while the network storage server remains online (available for servicing client requests), which includes enabling a user to approve or disapprove remedial changes before the changes are committed. The technique bypasses the usual consistency point process for new or modified data blocks representing potential remedial changes. At a consistency point, dirty data blocks representing the potential remedial changes are written to a change log file residing outside the volume. The modified data blocks are written in sequential order to logical blocks of the change log file. In response to a user input indicating that a potential change should be committed, the corresponding modified data blocks are read from the change log file in the order in which they were written to the change log file, and they are written to persistent storage in that order.

主权项

1. A method, comprising:
detecting errors in a volume of a network storage server while the network storage server remains available for servicing client requests; identifying a potential change to the volume for resolving an error, while the network storage server remains available for servicing the client requests; writing modified data blocks representing the potential change to a log which resides outside the volume to bypass automatic writing of data for resolving the error to a persistent storage facility of the network storage server and to preserve a consistent image of a file system of the network storage server; and in response to receiving a user input indicating that the potential change should be committed, committing the potential change to the volume by
reading the modified data blocks from the log, andwriting the modified data blocks to the persistent storage facility of the network storage server in an order in which the modified data blocks were read from the log.