Verify that the Search application is extracting file content on a regular basis by checking entries in the SystemOut.log file. During index building, files are ...
Best Practices. Always verify file integrity before extraction; Check available disk space; Use appropriate extraction tools; Preserve original compressed files.
Ie - unzip -t file.zip verifies all the CRCs of the files and the redundant copies of the metadata. In actuality it's probably just checking the metadata.