Jeff’s Note #
Unlike generic exam dumps, ADH analyzes this scenario through the lens of a Real-World Site Reliability Engineer (SRE).
For SOA-C02 candidates, the confusion often lies in assuming that increasing EBS volume size automatically updates the OS-level filesystem. In production, this is about knowing exactly how to manually expand the filesystem after EBS resizing on Windows or Linux EC2 instances. Let’s drill down.
The Certification Drill (Simulated Question) #
Scenario #
Crescent Solutions, a logistics software provider, manages its Windows-based EC2 instances with attached Amazon Elastic Block Store (EBS) volumes. To handle growing data, a SysOps engineer increased the size of an existing EBS volume from the EC2 Management Console. However, the additional capacity has not become available within the Windows filesystem.
The Requirement: #
Identify the most appropriate next step the SysOps engineer should take to make the new EBS volume size usable within the Windows OS.
The Options #
- A) Use an operating system utility to extend the filesystem to cover the new EBS capacity.
- B) Detach and then reattach the EBS volume to the EC2 instance.
- C) Restart the EC2 instance that the EBS volume is attached to.
- D) Create a snapshot of the EBS volume and restore a new, larger volume from the snapshot to replace the current volume.
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Correct Answer #
A) Use an operating system utility to extend the filesystem to cover the new EBS capacity.
Quick Insight: The SysOps Expansion Imperative #
When you increase an EBS volume size via the console or CLI, the underlying block device reflects the new size immediately, but the OS filesystem must be manually extended (using Windows Disk Management or Linux
resize2fs) to utilize the additional space.
Content Locked: The Expert Analysis #
You’ve identified the answer. But do you know the implementation details that separate a Junior from a Senior?
The Expert’s Analysis #
Correct Answer #
Option A
The Winning Logic #
When you increase the size of an Amazon EBS volume, the expansion propagates to the block device but does not automatically update the filesystem. On Windows, you must use Disk Management or PowerShell Resize-Partition cmdlet to extend the partition to occupy the new free space. On Linux, a tool like growpart (for partition) and resize2fs (for Ext4) or xfs_growfs (for XFS) is necessary. This approach allows dynamic expansion without instance downtime or volume replacement.
The Trap (Distractor Analysis): #
- Why not B? Reattaching the same volume won’t trigger filesystem changes; the OS still sees the old partition size.
- Why not C? Restarting is unnecessary because the kernel already sees the increased block device size.
- Why not D? Snapshotting and restoring a larger volume is complex, slow, and not required just to use expanded storage.
The Technical Blueprint #
Relevant SysOps CLI snippet to describe volume changes and extend partition on Windows: #
# Check current volume size in EC2 Linux instance
lsblk
# Rescan the disk to detect new size (Linux)
echo 1 > /sys/class/block/xvdf/device/rescan
# Extend partition (using growpart)
sudo growpart /dev/xvdf 1
# Resize filesystem
sudo resize2fs /dev/xvdf1
On Windows, use Disk Management GUI or PowerShell:
# List disks and partitions
Get-Partition
# Resize partition to max size
Resize-Partition -DiskNumber 1 -PartitionNumber 2 -Size (Get-PartitionSupportedSize -DiskNumber 1 -PartitionNumber 2).SizeMax
The Comparative Analysis #
| Option | Operational Overhead | Automation Level | Impact |
|---|---|---|---|
| A | Low - manual but immediate | Medium - scriptable | Correctly exposes new space without downtime |
| B | Medium - instance disruption | Low | Ineffective for filesystem size changes |
| C | High - unnecessary downtime | Low | No effect on filesystem size recognition |
| D | Very High - slow and manual | Low | Overkill and risks errors on volume swap |
Real-World Application (Practitioner Insight) #
Exam Rule #
“For SOA-C02, when EBS volume size is changed, always remember to manually extend the filesystem to access the new space.”
Real World #
“In production, automation scripts using SSM Run Command or custom CloudWatch alarms can monitor volume usage and trigger filesystem expansions to prevent manual intervention and reduce operational risk.”
(CTA) Stop Guessing, Start Mastering #
Disclaimer
This is a study note based on simulated scenarios for the SOA-C02 exam.