Lightsail Additional Attached Disks listed as /dev/xvd, but in Linux they appear as /dev/nvme. Find Mapping?

This discrepancy between the disk paths shown in the Lightsail interface and what you see in your Linux instance is a known situation, and there are a few things to understand about it:

1. Device naming: On June 29, 2023, AWS updated the underlying hardware for Lightsail instances. As a result, instances created after this date display device names as '/dev/nvme0n1' instead of the previous '/dev/xvda' format.

2. Nitro instances: The '/dev/nvme' naming convention is dictated by the storage device driver used in Nitro instances. This can lead to differences in how disks are identified compared to non-Nitro instances.

3. Varying identifiers: The disk identifiers can change between reboots, which can cause issues with mounting if you're relying on specific device names.

To address this and find a stable mapping between the Lightsail interface and your Linux system, you can try the following:

1. Use disk UUIDs: Instead of relying on device names, you can use the disk's UUID to create a stable reference. You can find the UUID of a disk using the 'blkid' command in Linux and then use this in your '/etc/fstab' file for consistent mounting.

2. AWS CLI: You can use the AWS CLI to get more detailed information about your Lightsail disks. The 'get-disk' command can provide you with details like the disk's ARN, size, and attachment state, which might help you correlate with what you see in the Linux system.

3. Check system logs: You might find information in system logs that can help you map the Lightsail disk names to the device names in your Linux system.

4. Use lsblk command: This command in Linux can show you the size and mount points of attached disks, which you can compare with the information in the Lightsail interface.

While there isn't a direct, built-in way to see the Lightsail disk names within the Linux system, using a combination of these methods should help you establish a reliable mapping between what you see in Lightsail and on your Linux instance.

Sources
Lightsail attached disk has wrong (and varying) disk path | AWS re:Post
Create and attach Lightsail block storage disks to Linux instances - Amazon Lightsail
Lightsail examples using AWS CLI - AWS SDK Code Examples

get-disk will provide the arn and the supportCode that aren't available in the web interface, but none of that information is exposed to Linux, (to my knowledge). There is still no way to know which Additional Attached Disks in Lightsail is mapped to a specific device in Linux. It leaves us flying blind.