public static void moveShard(final String volumePath,
                                 final Integer oldIndexId,
                                 final String indexUuid) {
        Path path = Paths.get(volumePath);

        if (!Files.isDirectory(path)) {
            LOGGER.error("Volume path not found: " + volumePath);
        } else if (oldIndexId != null) {
            // If we have a legacy shard then see if we can create a path for it.
            Path legacyPath = path.resolve("index");
            legacyPath = legacyPath.resolve(String.valueOf(oldIndexId));
            if (Files.isDirectory(legacyPath)) {
                Path newPath = path.resolve("index");
                newPath = newPath.resolve(indexUuid);
                move(legacyPath, newPath);
            }
        }
    }
@return A map of index UUIDs to lists of the volumes they use. We'll need both, hence the map.
stroom-legacy/stroom-legacy-db-migration/src/main/java/stroom/legacy/db/migration/V07_00_00_1502__Index.java