private boolean initRocksDB(final StoreEngineOptions opts) {
        RocksDBOptions rocksOpts = opts.getRocksDBOptions();
        if (rocksOpts == null) {
            rocksOpts = new RocksDBOptions();
            opts.setRocksDBOptions(rocksOpts);
        }
        String dbPath = rocksOpts.getDbPath();
        if (Strings.isNotBlank(dbPath)) {
            try {
                FileUtils.forceMkdir(new File(dbPath));
            } catch (final Throwable t) {
                LOG.error("Fail to make dir for dbPath {}.", dbPath);
                return false;
            }
        } else {
            dbPath = "";
        }
        final String childPath = "db_" + this.storeId + "_" + opts.getServerAddress().getPort();
        rocksOpts.setDbPath(Paths.get(dbPath, childPath).toString());
        this.dbPath = new File(rocksOpts.getDbPath());
        final RocksRawKVStore rocksRawKVStore = new RocksRawKVStore(getRocksDBGroup());
        if (!rocksRawKVStore.init(rocksOpts)) {
            LOG.error("Fail to init [RocksRawKVStore].");
            return false;
        }
        this.rawKVStore = rocksRawKVStore;
        return true;
    }
Storage engine, there is only one instance in a node,
containing one or more {@link RegionEngine}.

@author jiachun.fjc
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/StoreEngine.java