Method, electronic device and computer program product for creating metadata index

A method for indexing metadata for metadata of a multi-node computing system in which operation of the multi-node computing system depends on a consistency of the metadata across the multi-node computing system, comprising:

• obtaining, by an electronic device of the multi-node computing system, a metadata index to provide metadata inconsistency identification;
• obtaining, by the electronic device, a remote metadata index from a second electronic device of the multi-node computing system, the metadata index and the remote metadata index indexing a same set of metadata distributed across the multi-node computing system, the set of metadata being redundantly stored across the multi-node computing system;
• identifying, by the electronic device, a second-level index of the metadata index and a corresponding second-level index of the remote metadata index;
• identifying, by the electronic device, an inconsistency between the metadata index and the remote metadata index, the inconsistency being based on the second-level index being different from the corresponding second-level index;
• obtaining a second indication contained in the second-level index, the second indication indicating a position of a metadata item that is redundantly stored in the electronic device for the second electronic device, the metadata item being inconsistent with a corresponding metadata item stored in the second electronic device;
• and
• accessing the metadata item based on the position.

An electronic device of a multi-node system in which operation of the multi-node system depends on a consistency of metadata across the multi-node system, comprising:

• a processor;
• and
• a memory storing computer program instructions, the processor executing the computer program instructions in the memory to control the electronic device to perform operations for creating a metadata index for metadata of a multi-node system in which operation of the multi-node system depends on a consistency of the metadata across the multi-node system, the operations comprising:
• identifying all locations of copies of a metadata item within the multi-node system, one of the locations being on a first electronic device of the multi-node system and a second of the locations being on a second electronic device of the multi-node system;
• generating a first-level index for each of the copies of the metadata index;
• inserting an indication into each first-level index to indicate a position of a corresponding copy of the metadata item, the position usable to identify the locations of the corresponding copy of the metadata item;
• generating a first second-level index for the metadata index to index a first set of the first-level index, the first set of the first-level index all being associated with copies of the metadata item having locations of the first electronic device;
• inserting a second indication into the first second-level index that directly specifies a first set of positions associated with the copies of the metadata item having the locations of the first electronic device;
• generating a second second-level index for the metadata index to index a second set of first-level index, the second set of first-level index all being associated with copies of the metadata item having locations of the second electronic device;
• inserting a third indication into the second second-level index that directly specifies a second set of positions associated with the copies of the metadata item having the locations of the second electronic device;
• identifying an inconsistency between the metadata index and a remote metadata index from the second electronic device, the inconsistency being based on the second second-level index of the metadata index being different from a corresponding second second-level index of the remote metadata index, wherein the metadata index and the remote metadata index are generated using a same process;
• and
• updating the metadata index based on the identified inconsistency to obtain an updated metadata index that is consistent with the remote metadata index.

A computer program product being tangibly stored on a non-transitory computer-readable medium and comprising computer-executable instructions, the computer-executable instructions usable to create a metadata index for metadata of a multi-node system in which operation of the multi-node system depends on a consistency of the metadata across the multi-node system, the computer-executable instructions when executed, causing a computer to perform operations, the operations comprising:

• identifying all locations of copies of a metadata item within the multi-node system, one of the locations being on a first electronic device of the multi-node system and a second of the locations being on a second electronic device of the multi-node system;
• generating a first-level index for each of the copies of the metadata index;
• inserting an indication into each first-level index to indicate a position of a corresponding copy of the metadata item, the position usable to identify the locations of the corresponding copy of the metadata item;
• generating a first second-level index for the metadata index to index a first set of the first-level index, the first set of the first-level index all being associated with copies of the metadata item having locations of the first electronic device;
• inserting a second indication into the first second-level index that directly specifies a first set of positions associated with the copies of the metadata item having the locations of the first electronic device;
• generating a second second-level index for the metadata index to index a second set of first-level index, the second set of first-level index all being associated with copies of the metadata item having locations of the second electronic device;
• inserting a third indication into the second second-level index that directly specifies a second set of positions associated with the copies of the metadata item having the locations of the second electronic device;
• identifying an inconsistency between the metadata index and a remote metadata index from the second electronic device, the inconsistency being based on the second second-level index of the metadata index being different from a corresponding second second-level index of the remote metadata index, wherein the metadata index and the remote metadata index are generated using a same process;
• and
• updating the metadata index based on the identified inconsistency to obtain an updated metadata index that is consistent with the remote metadata index.