AWS Instance store

Instance store 速度超強 

測試數據：
https://gist.github.com/ktheory/3c3616fca42a3716346b

Instance-store is over 5x faster than EBS-SSD for uncached reads.Instance-store and EBS-SSD are equivalent for cached reads.Instance-store is over 10x faster than EBS-SSD for writes.

不是每種機器等級都有支援：

Some instance families, such as T2 and T1, do not support instance store volumes at all.

資料揮發時機：

重開機沒事兒, 不用自己嚇自己, 只有stop, crash會讓資料消失.

Ephemeral storage or instance-store DOES persist across reboots of an instance! It does not persist across a stop/start, nor a termination, nor some instance hardware failures.