Commvault Systems, Inc.
SYNCHRONIZING METADATA IN A DATA STORAGE PLATFORM COMPRISING MULTIPLE COMPUTER NODES

Abstract:

A client machine writes to a virtual disk on a remote storage platform. Metadata is generated and stored in replicas on different nodes of the storage platform. A modified log-structured merge tree is used to store and compact string-sorted tables of metadata. During file storage and compaction, a consistent file identification scheme is used across all metadata nodes. A fingerprint file is calculated for each SST (metadata) file on disk that includes hash values corresponding to regions of the SST file. To synchronize, the fingerprint files of two SST files are compared, and if any hash values are missing from a fingerprint file then the key-value-timestamp triplets corresponding to these missing hash values are sent to the SST file that is missing them. The SST file is compacted with the missing triplets to create a new version of the SST file. The synchronization is bi-directional as between distinct computer nodes.