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

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 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, and
• writing 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.

A network storage server, comprising:

• a memory containing machine readable medium comprising machine executable code having stored thereon instructions for performing a method of maintaining data consistency;
• a processor coupled to the memory, the processor configured to execute the machine executable code to:
• service read and write requests directed to a file system from a plurality of storage client on a network, including writing data to persistent storage in response to write requests by using a write allocation process;
• execute a file system error detection process to detect an error in the file system;
• and
• identify a potential change to the file system for resolving the error while the network storage server remains available for servicing client requests, to enable a user to approve or disapprove the potential change before the potential change is committed to the file system, and to commit the potential change to the file system when the potential change is approved by the user, such that the write allocation process is not invoked to commit the potential change to the file system after the user approves the potential change.

A network storage server, comprising:

• a memory containing machine readable medium comprising machine executable code having stored thereon instructions for performing a method of maintaining data consistency;
• a processor coupled to the memory, the processor configured to execute the machine executable code to:
• detect an error in a file system of the network storage server while the network storage server remains available for servicing client requests;
• identify a potential change to the file system for resolving the error while the network storage server remains available for servicing client requests;
• and
• enable a user to approve the potential change before the potential change is committed to the file system.

A non-transitory machine readable medium having stored thereon instructions for performing a method of handling a read request, comprising machine executable code which when executed by at least one machine, causes the machine to:

• detect errors in a volume of a network storage server while the network storage server remains available for servicing client requests;
• identify a potential change to the volume for resolving an error, while the network storage server remains available for servicing client requests;
• write modified data blocks representing the potential change to a log file 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;
• in response to receiving a read request for reading a data block of a data file in the volume, determine whether the log file residing outside the volume includes a modified version of the data block;
• and
• satisfy the read request by reading the modified version of the data block from the log file, if the log file includes the modified version of the data block.