参见:https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/InstanceStorage.html # instance-store-volumes

The data in an instance store persists only during the lifetime of
 its associated instance. If an instance reboots (intentionally or
 unintentionally), data in the instance store persists. However, 
data in the instance store is lost under any of the following
 circumstances:

- The underlying disk drive fails

- The instance stops

- The instance hibernates

- The instance terminates

对于EC2实例

Stop & Start != Reboot

对于临时存储(实例存储) 停止导致数据丢失 重启不会

According to AWS documentation [https://aws.amazon.com/premiumsupport/knowledge-center/instance-store-vs-ebs/] instance store volumes is not persistent through instance stops, terminations, or hardware failures. Any AMI created from instance stored disk doesn't contain data present in instance store so all instances launched by this AMI will not have data stored in instance store. Instance store can be used as cache for applications running on instance, for all persistent data you should use EBS.

参见:https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/InstanceStorage.html # instance-store-volumes

The data in an instance store persists only during the lifetime of
 its associated instance. If an instance reboots (intentionally or
 unintentionally), data in the instance store persists. However, 
data in the instance store is lost under any of the following
 circumstances:

- The underlying disk drive fails

- The instance stops

- The instance hibernates

- The instance terminates

要清楚地回答@Dean的问题:ebs类型的根存储似乎不是短暂的。数据在重启过程中是持久的，实际上使用ebs支持的根卷是“短暂的”，这没有任何意义。这与基于图像的根卷没有什么不同。

ephemeral只是从Amazon EC2实例存储支持的AMI启动实例时根卷的另一个名称

所有东西都存储在ephemeral上。

如果您已经从AMI启动实例，由EBS卷支持，那么您的实例没有临时的。