我在官网上找了 它是这样写的：
Close all but one Titan instance in the cluster
Connect to the single instance
Ensure all running transactions are closed
Ensure no new transactions are started (i.e. the cluster must be offline)
Open the management API
Change the configuration option(s)
Call commit which will automatically shut down the graph instance
Restart all instances
可我比较菜 不是很明白 求大神指点