private static OutputStream metaFile() throws java.io.IOException {
        String fn = getDefaults().underVespaHome(DBDIR + "logfiles." + dayStamp());
        File dir = new File(fn).getParentFile();
        try {
            Files.createDirectories(dir.toPath());
        } catch (IOException e) {
            System.err.println("Failed creating logfiledb directory '" + dir.getPath() + "': " + e.getMessage());
        }
        Path path = Paths.get(fn);
        return Files.newOutputStream(path, CREATE, APPEND);
    }
@author arnej

This class takes care of saving meta-data about a log-file,
ensuring that we can enact policies about log retention.
vespalog/src/main/java/com/yahoo/log/LogFileDb.java