SmartScan: Efficient Metadata Crawl for Storage Management Metadata Querying in Large File Systems
SmartScan is a metadata crawl tool that exploits patterns in metadata changes to significantly improve the efficiency of support for file-system-wide metadata querying, which is an important tool for administrators. In most environments, support for metadata queries is provided by databases populated and refreshed by calling stat () on every file in the file system. For large file systems, where such storage management tools are most needed, it can take many hours to complete each scan, even if only a small percentage of the files have changed. To address this issue, the authors identify patterns in metadata changes that can be exploited to restrict scanning to the small subsets of directories that have recently had modified files or that have high variation in file change times.