Amazon Elastic Block Store and EC2 drive

Question

I am fairly new with AWS(just have a free AWS EC2 instance to test out AWS stuff) so the question might sound silly.

Today I got a mail that my Amazon Elastic Block Storeage has reached 85% usage on my free AWS account which is about 25 GB of the allocated 30 GB. From what I read today, Amazon EBS is a persistent store used for EC2 instances.

However I can see in my EC2 instance that df -h just show 2 GB usage and available disk as 28 GB as this is just my practice instance.

Am I missing some important piece of information here?

Almallah

What was the specific wording of the email? There are a couple things that might be considered for EBS volumes. Snapshot storage is one of them, and I am curious if that is it. aws.amazon.com/free – Demi

Hi Nocholoas, I think this is different. The mail goes something like this: "Your AWS account XXXX has exceeded 85% of the usage limit for one or more AWS Free Tier-eligible services for the month of May. AWS Free Tier Usage as of 05/27/2018 AWS Free Tier Usage Limit 25.2 GB-Mo 30 GB of Amazon Elastic Block Storage in any combination of General Purpose (SSD) or Magnetic". I did a df -h on my ec2 instance is just showing 2 GB of disc space used so I am not sure why these two disc outputs are not is sync. – Almallah

Answer 1

EBS devices are block devices.

This means the service does not know how much data you actually store on them -- it only knows how much storage space you allocated. So, the results of df -h don't matter. The actual size of the volume is all that matters -- that's the basis for billing. The rest of the space (that space you aren't current using) is still storing something, even it if's just 0's, but the service is unaware of what you've stored. (Other storage services like S3 and EFS bill for actual data stored, because they are not block storage services.)

Now, the free tier allows 30 gigabyte-months of EBS volume usage. You can use more than that, but this is the limit that's provided for free. You'll be billed for any more than this.

A gigabyte-month means 1 gigabyte of block storage space, allocated for 1 month, regardless of how you use it.

Also, 2 gigabytes of allocated storage for 15 days is 1 GB-month.

Also, 10 gigabytes of allocated storage for 3 days is 1 GB-month.

...etc.

The free tier, then, would allow you to have a 30 GB volume for 30 days, or a 60 GB volume for 15 days, or even a 900 GB volume... but you could have it for only 1 day. But to avoid continuing charges, such a volume must be deleted -- not just the files on the volume.

The warning message was correct. If you have a 30 GB volume in place for 26 days, then you have used 26 GB-months of storage, which is 86.7% of the free tier limit of 30 GB-months.

Grandnephew

Hi Michael, Yes that was the issue as confirmed by the amazon team. So it is just the quota which is getting expired and in the free subscription it will be again start from next month without effecting any files on the EC2 instance. – Almallah

@Pulkit some people don't know this, but free tier account are real accounts. The limits are only limits on what is actually free. You can always exceed the limits, and if you do, you are billed for whatever isn't covered by the free tier. That is what the warning email was actually telling you -- not that your usage would be disallowed, but rather that you were on track to go beyond "free" -- however, near the end of the month, it is pretty normal to get close to the free limits. If you see these much earlier in the month, or numbers are out of proportion, then that is more of a concern. – Grandnephew

Answer 2

For anyone stumbling upon this in 2021:

Free Trial provides 750 Hrs of Amazon EC2 Linux t2.micro and 750 Hrs of Amazon EC2 Windows t2.micro per month. However, both of them will add in to the free 30GB EBS pool. So make sure the memories allotted to both the VMs sum up to 30 GB or less.

Austin

Answer 3

There are limits on the type and number of resources you can allocate for each account.

It sounds like in your case, you are allowed to create a total of 30GB of EBS volumes. Once you allocate an EBS volume, in your case 25GB, it counts against that limit, even if it isn't used.

There is a section in the EC2 console (near the top) called "Limits" that will show you what your limits are, and what you are using.

Most limits can be extended with a simple support ticket.

Weatherproof

I think this is something different The mail goes something like this: "Your AWS account XXXX has exceeded 85% of the usage limit for one or more AWS Free Tier-eligible services for the month of May. AWS Free Tier Usage as of 05/27/2018 AWS Free Tier Usage Limit 25.2 GB-Mo 30 GB of Amazon Elastic Block Storage in any combination of General Purpose (SSD) or Magnetic". I did a df -h on my ec2 instance is just showing 2 GB of disc space used so I am not sure why these two disc outputs are not is sync – Almallah