Introduction
In the world of cloud computing, it's important to understand the various storage options available to you. Amazon Web Services (AWS) offers two main types of storage for its Elastic Compute Cloud (EC2) instances: instance store and Amazon Elastic Block Store (EBS). In this blog post, we'll discuss the key differences between the two and help you determine which one is the best fit for your needs.
Definition of EC2 instance store
Instance store is a type of temporary storage that is physically attached to the host computer of an EC2 instance. It is also known as ephemeral storage because it is not persisted when the instance is stopped or terminated.
Definition of Amazon EBS
Amazon EBS is a persistent storage service that allows you to create and attach one or more storage volumes to an EC2 instance. These volumes are independent from the host computer and can be detached and attached to other instances as needed.
Performance
In terms of performance, instance store tends to be faster than EBS because it is physically attached to the host computer. However, the performance of EBS has improved significantly over the years and it is now able to deliver high levels of input/output operations per second (IOPS) for workloads that require it.
Durability
One major advantage of Amazon EBS over instance store is durability. Because EBS volumes are stored on separate physical servers, they are less vulnerable to data loss due to hardware failure. On the other hand, instance store data is at risk of being lost if the host computer fails.
Instance store data is temporary and only persists for the duration of the associated instance. If the instance reboots, the data in the instance store will still be present. However, the data will be lost under the following circumstances:
- The underlying disk drive fails
- The instance stops
- The instance hibernates
- The instance terminates
It is important to note that instance store should not be relied upon for storing valuable, long-term data. Instead, consider using more durable storage options such as Amazon S3, Amazon EBS, or Amazon EFS for this purpose.
Cost
In terms of cost, instance store is generally cheaper than EBS because you don't have to pay for the storage separately. However, EBS allows you to pay for only the storage you need and scale up or down as needed, which can be more cost-effective for certain workloads.
Support
It is important to note that not all EC2 instances support instance storage, and even among those that do, the amount of storage available can vary. To get a list of all instance types that support instance storage, you can use the following AWS CLI command:
aws ec2 describe-instance-types \
--filters "Name=instance-type,Values=*" "Name=instance-storage-supported,Values=true" \
--query "InstanceTypes[].[InstanceType, InstanceStorageInfo.TotalSizeInGB]" \
--output table | sort
For example, T2 and T3 instances do not support instance storage. You can find more information on EC2 instance storage in the AWS EC2 instance storage user guide.
Conclusion
In summary, both EC2 instance store and Amazon EBS offer unique benefits and trade-offs. Instance store is a fast and cost-effective option for temporary storage, but it is not durable. Amazon EBS is a more durable option that allows you to scale your storage needs, but it comes at a higher cost. Ultimately, the right choice for your needs will depend on the specific requirements of your workload.
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