SOLVED – Why Amazon EC2 instance has only 8 GB spaces

In this tutorial, we will show you SOLVED problems Why the Amazon EC2 instance has only 8 GB spaces. When launching an Amazon EC2 instance, you may have encountered a common frustration: despite allocating a larger EBS volume during setup, your instance only shows 8 GB of available space when you check with commands like df -h. This discrepancy can be alarming, especially when you’re preparing to deploy applications that require substantial storage capacity. The good news is that this issue is entirely solvable, and understanding the underlying causes will help you manage your EC2 storage more effectively going forward.

Understanding Amazon EC2 Storage Basics

Amazon Elastic Compute Cloud (EC2) is a core service in the AWS ecosystem that provides scalable computing capacity in the cloud. It’s designed to make web-scale cloud computing easier for developers by offering virtual servers that can be launched on demand. When it comes to storage, EC2 offers several options that serve different needs and use cases.

Amazon EC2 Overview

EC2 instances are virtual machines running in AWS data centers. They function like traditional servers but with the added advantages of scalability, reliability, and the ability to provision resources within minutes. Each EC2 instance type is optimized for specific purposes, with varying combinations of CPU, memory, storage, and networking capacity.

EC2 Storage Options

Amazon provides several storage options for EC2 instances, each with distinct characteristics:

Elastic Block Store (EBS) volumes deliver persistent block-level storage that can be attached to and detached from your EC2 instances. EBS volumes persist independently from the running life of an instance, making them ideal for primary storage needs. They can be backed up using snapshots stored in Amazon S3.

Instance store volumes provide temporary block-level storage directly attached to the host computer. These volumes offer high I/O performance but only persist during the life of the associated instance. Any data stored here is lost when the instance stops or terminates.

Amazon S3 provides object storage accessible from anywhere on the web. While not directly mounted to EC2 instances like a file system, S3 is excellent for storing backups, static content, and data that doesn’t require filesystem-level access.

Amazon EFS and Amazon FSx offer scalable file storage solutions that can be mounted across multiple EC2 instances simultaneously, enabling shared access to files.

Default Storage Configurations

Most Amazon Machine Images (AMIs) come with pre-configured default storage settings, which typically include an 8 GB root volume. This default size is sufficient for the operating system and basic applications, but may not accommodate additional software or data your application requires. Understanding this default configuration is key to resolving the 8 GB space limitation.

Why Your EC2 Instance Shows Only 8 GB Space

The 8 GB space limitation is one of the most common issues encountered by AWS users. To solve it effectively, you need to understand exactly why it happens.

Default AMI Configurations

When you launch an EC2 instance, the system is created from an Amazon Machine Image (AMI). Most standard AWS-provided AMIs come with root volumes that are pre-configured with 8 GB partitions. Even if you specify a larger EBS volume size during instance creation, the actual file system inside the volume may still be limited to 8 GB due to the way the AMI is configured.

Volume vs. Partition Size Distinction

There’s an important distinction between the volume size and the partition size that causes this issue:

• EBS volume size: This is the total raw storage capacity you allocate when creating or modifying an EBS volume.
• Partition size: This is how the space within the volume is divided and organized.
• File system size: This refers to the formatted space available within a partition where you can actually store and retrieve data.

When you increase an EBS volume size, you’re only changing the raw storage capacity. The partition and file system must be expanded separately to utilize that additional space.

Common Scenarios Leading to the 8 GB Limitation

You might encounter the 8 GB limitation in several common scenarios:

1. You’ve launched a new instance with a larger allocated EBS volume (like 50 GB), but the OS only recognizes 8 GB.
2. You’ve resized an existing volume through the AWS console, but the file system hasn’t been updated to recognize the additional space.
3. Your instance type has storage constraints that affect how volumes are recognized and used.

Understanding these scenarios helps diagnose exactly what’s happening when you face this issue.

Diagnosing Your EC2 Storage Issue

Before implementing a solution, it’s important to properly diagnose your storage situation. Several Linux commands can help you understand the current state of your storage.

Essential Linux Commands for Storage Analysis

Check File System Usage:

df -h

This command shows the amount of disk space used and available on mounted file systems. It will typically show your root volume as /dev/xvda1 or similar, with only 8 GB of total space.

Examine Block Devices:

lsblk

This command lists information about all available block devices. It will show you the actual size of the underlying volume (which might be larger than 8 GB) and the size of the partition (which is likely 8 GB).

Analyze Directory Usage:

du -sh /path/to/directory

This helps identify which directories are consuming the most space, which can be useful for troubleshooting space issues.

Understanding the AWS Console Storage Information

The EC2 console provides valuable information about your volumes. Navigate to EC2 > Elastic Block Store > Volumes to see all your EBS volumes. Here, you can check:

• Volume size: The total size you’ve allocated
• State: Whether the volume is available or in-use
• Volume type: Whether it’s a gp2 (General Purpose SSD), io1 (Provisioned IOPS SSD), etc.
• Attachment information: Which EC2 instance the volume is attached to

You should also check the “Delete on Termination” setting for your volumes, as this determines whether the volume will be automatically deleted when the associated instance is terminated.

Step-by-Step Solutions for the 8 GB Space Limitation

Now that you understand the cause of the problem, let’s explore detailed solutions to resolve the 8 GB space limitation.

Solution 1: Resizing the Existing File System

If you’ve already modified your EBS volume size through the AWS console, you’ll need to extend the partition and file system to use the additional space. The process differs slightly depending on your file system type.

For Linux instances with ext4 file systems (most common):

1. Check the current state of your storage:

   df -h
   lsblk

2. Install necessary tools (if not already present):

   sudo apt-get update
   sudo apt-get install cloud-guest-utils

3. Grow the partition to use all available space:

   sudo growpart /dev/xvda 1

   Note the space between /dev/xvda and 1, where 1 represents the partition number.

4. Resize the file system to fill the expanded partition:

   sudo resize2fs /dev/xvda1

5. Verify the new size:

   df -h

For XFS file systems:

The process is similar, but you’ll use xfs_growfs instead of resize2fs:

sudo xfs_growfs /mount_point

Where /mount_point is where the XFS file system is mounted (often / for the root file system).

Solution 2: Properly Allocating Storage During Instance Creation

To avoid the 8 GB limitation when creating new instances:

1. In the EC2 launch wizard, proceed to the “Storage” step.
2. Modify the size of the root volume to your desired value (e.g., 50 GB instead of the default 8 GB).
3. Optionally, change the volume type based on your performance needs.
4. Complete the instance launch process.

Even with this approach, you may still need to resize the file system after first boot using the commands described in Solution 1, as some AMIs might still create an 8 GB partition regardless of the volume size.

Using the AWS CLI, you can specify the volume size during instance creation:

aws ec2 run-instances --image-id ami-xxxxxxxx --instance-type t2.micro --block-device-mappings "[{\"DeviceName\":\"/dev/xvda\",\"Ebs\":{\"VolumeSize\":50,\"DeleteOnTermination\":true}}]"

Solution 3: Attaching and Using Additional EBS Volumes

Rather than expanding the root volume, you can attach additional EBS volumes:

1. Create a new EBS volume in the AWS console (EC2 > Elastic Block Store > Volumes > Create Volume).
2. Attach it to your instance by selecting the volume, clicking “Actions,” and choosing “Attach Volume.”
3. Connect to your instance and identify the new volume:

   lsblk

   It will appear as a device like /dev/xvdf.

4. Format the new volume (skip this step if the volume already has data):

   sudo mkfs -t ext4 /dev/xvdf

5. Create a mount point and mount the volume:

   sudo mkdir /data
   sudo mount /dev/xvdf /data

6. To make the mount persistent across reboots, add an entry to /etc/fstab:

   echo '/dev/xvdf /data ext4 defaults,nofail 0 2' | sudo tee -a /etc/fstab

This approach gives you the flexibility of keeping the system files on the root volume while storing data on separate volumes.

Managing EC2 Instance Storage for Different Use Cases

Different applications have different storage requirements. Let’s explore optimizing EC2 storage for common use cases.

Database Storage Considerations

Databases typically require high-performance, reliable storage with consistent I/O characteristics:

• For MySQL, PostgreSQL, or other relational databases, consider using Provisioned IOPS SSD (io1/io2) volumes for the data directories.
• Separate data files, log files, and temporary files onto different volumes for better performance.
• For write-intensive workloads, ensure you provision enough IOPS to handle peak loads.
• Consider using multiple EBS volumes in a RAID 0 configuration for higher throughput, though this increases the risk of data loss if any one volume fails.

Web Server Storage Best Practices

Web servers generally have different storage patterns than databases:

• Store static content (images, CSS, JavaScript) on separate volumes or consider using Amazon S3 with CloudFront for better performance and scalability.
• Keep logs on separate volumes to prevent log growth from affecting the root volume.
• For content management systems, separate the application code from user-uploaded content.

Application Server Storage Configuration

Application servers may have unique storage requirements:

• Consider using instance store volumes for temporary files and caches if your application can handle the ephemeral nature of this storage.
• Store application logs on a separate volume and implement log rotation to prevent disk space issues.
• For Java applications, ensure there’s enough space for heap dumps in case of memory issues.

Avoiding Common EC2 Storage Mistakes

Even experienced AWS users can make mistakes when managing EC2 storage. Here are some common pitfalls to avoid.

Ignoring Delete on Termination Settings

By default, the root EBS volume is configured to be deleted when the EC2 instance is terminated. This behavior is controlled by the “Delete on Termination” flag:

• For root volumes, this flag is typically set to “Yes” by default.
• For additional volumes, it’s set to “No” by default.

If you store important data on your root volume, either change this setting or ensure you have reliable backups. Conversely, if you don’t change this setting for non-root volumes that you no longer need, you might end up with orphaned volumes that continue to accrue charges.

Confusing Ephemeral Storage with EBS

Instance store (ephemeral) volumes and EBS volumes serve different purposes:

• Instance store volumes are physically attached to the host computer, offer high I/O performance, but do not persist beyond the life of the instance.
• EBS volumes are network-attached storage that persists independently of the instance lifecycle.

Using instance store volumes for persistent data without proper backup strategies can lead to data loss when instances are stopped or terminated.

Overlooking Instance Type Storage Specifications

Different EC2 instance types have different storage capabilities:

• Some instance types come with pre-configured instance store volumes.
• Storage-optimized instances (like the d-series) offer much higher local storage capacity and performance.
• Memory-optimized or compute-optimized instances might prioritize other resources over storage.

Choose instance types that match your storage performance requirements, or supplement them with appropriately configured EBS volumes.

Advanced EC2 Storage Optimization

For users with demanding storage requirements, AWS offers several advanced options for optimizing storage performance and cost.

EBS Volume Types and Performance

AWS offers several EBS volume types, each optimized for different use cases:

• General Purpose SSD (gp2/gp3): Balanced price and performance for a wide range of workloads.
• Provisioned IOPS SSD (io1/io2): Highest performance for I/O-intensive applications like databases.
• Throughput Optimized HDD (st1): Low-cost HDD volume designed for frequently accessed, throughput-intensive workloads.
• Cold HDD (sc1): Lowest cost HDD volume designed for less frequently accessed workloads.

Select the volume type that best matches your performance requirements and budget. For high-performance needs, consider using multiple EBS volumes in a RAID configuration.

Cost Optimization Strategies

To optimize storage costs:

• Regularly audit your volumes to identify and remove unused or underutilized volumes.
• Consider using Amazon S3 for infrequently accessed data rather than keeping it on EBS volumes.
• Use the right storage type for each workload; don’t pay for Provisioned IOPS when General Purpose SSDs would suffice.
• Implement automated snapshot lifecycle policies to maintain cost-effective backups.

Case Study: Resolving the 8 GB Limitation in Production

Let’s examine a real-world scenario of resolving the 8 GB limitation. A web hosting company was deploying a content management system on EC2 instances. They provisioned instances with 100 GB EBS volumes but found that the instances only had 8 GB of usable space.

The company had to resolve this issue without downtime, as these were production systems already serving customers. They implemented the following solution:

1. They verified the actual volume size using the AWS console and confirmed it was indeed 100 GB.
2. They connected to each instance via SSH and ran diagnostic commands:

   df -h
   lsblk

   This confirmed that while the EBS volume was 100 GB, the partition and file system were only 8 GB.

3. Without rebooting, they expanded the partition:

   sudo growpart /dev/xvda 1

4. They then expanded the file system:

   sudo resize2fs /dev/xvda1

5. A final check confirmed the full 100 GB was now available:

   df -h

This solution was implemented during a low-traffic period and required no downtime. The company later implemented an automated script as part of their instance initialization process to handle this automatically for new instances.