Amazon EC2 Instance Store

You can specify instance store volumes for an instance only when you launch it. 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 the following circumstances:

Therefore, do not rely on instance store for valuable, long-term data. Instead, you can build a degree of redundancy (for example, RAID 1/5/6), or use a file system (for example, HDFS and MapR-FS) that supports redundancy and fault tolerance. You can also back up data periodically to more durable data storage solutions such as Amazon S3 or Amazon EBS.

You can't detach an instance store volume from one instance and attach it to a different instance. If you create an AMI from an instance, the data on its instance store volumes isn't preserved and isn't present on the instance store volumes of the instances that you launch from the AMI.

The instance type determines the size of the instance store available and the type of hardware used for the instance store volumes. Instance store volumes are included as part of the instance's hourly cost. You must specify the instance store volumes that you'd like to use when you launch the instance, and then format and mount them before using them. You can't make an instance store volume available after you launch the instance. For more information, see Add Instance Store Volumes to Your EC2 Instance.

Some instance types use solid state drives (SSD) to deliver very high random I/O performance. This is a good option when you need storage with very low latency, but you don't need the data to persist when the instance terminates or you can take advantage of fault-tolerant architectures. For more information, see SSD Instance Store Volumes.

The following table provides the quantity, size, type, and performance optimizations of instance store volumes available on each instance type.

* Volumes attached to certain instances will suffer a first-write penalty unless initialized. For more information about initializing instance store volumes, see Optimizing Disk Performance for Instance Store Volumes.

** SSD-based instance store volumes that support TRIM instructions are not pre-formatted with any file system. However, you can format volumes with the file system of your choice after you launch your instance. For more information, see Instance Store Volume TRIM Support.

† The c1.medium and m1.small instance types also include a 900 MB instance store swap volume, which may not be automatically enabled at boot time. For more information, see Instance Store Swap Volumes.