The total size of all files added to this index (including documents indexed multiple times)

The difference between TotalFileSize and TotalDataSize is in the way containers are handled. TotalFileSize includes the size of container files such as ZIP files, but not their contents. TotalDataSize includes the size of the contents of container files, but not the size of the container. TotalFileSize is supported only in indexes created with dtSearch versions 7.94 and later.