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One of the classes of Job Engine jobs uses a ‘changelist’, rather than a full LIN-based scan, in order to discover its scope of work. The changelist approach analyzes two snapshots to find the LINs which changed (delta) between the snapshots, and from there determines the exact changes.
SyncIQ replication and the File System Analyze (FSAnalyze) cluster analytics are good examples of a job that leverages snapshot deltas and the ChangelistCreate mechanism.
The FilePolicy and FSAnalyze jobs in OneFS 8.2 and later automatically share the same snapshots and index, created and managed by the IndexUpdate job. When a cluster running FSAnalyze is upgraded to OneFS 8.2, the legacy FSAnalyze index and snapshots are removed and replaced by new snapshots the first time that IndexUpdate is run. The new index stores considerably more file and snapshot attributes than the old FSA index. Until the IndexUpdate job effects this change, FSA keeps running on the old index and snapshots.