# Migrate data from CentOS to AlmaLinux on Lightsail
Migrating from CentOS to AlmaLinux is a straightforward process by which you move data from one instance in Lightsail to another. This topic outlines two options that you can use to migrate your data.
For more information see the AlmaLinux documentation on the [https://wiki.almalinux.org/](https://wiki.almalinux.org/) site.
**Contents**
+ [Prerequisites](#amazon-lightsail-migrate-centos-to-almalinux-prerequisites)
+ [(Optional) Use secure copy (scp) to transfer files between instances](#amazon-lightsail-migrate-centos-to-almalinux-scp)
+ [(Optional) Move the block storage disk from the CentOS instance to the AlmaLinux instance](#amazon-lightsail-migrate-centos-to-almalinux-copy-disk)
## Prerequisites
+ If you haven't already, create an AlmaLinux Lightsail instance. For more information, see [Launch and set up an AlmaLinux instance on Lightsail](amazon-lightsail-quick-start-guide-almalinux.md).
+ Create a snapshot of the disk you plan to move to your AlmaLinux instance. For more information, see [Create Lightsail block storage disk snapshots for backup or baseline](create-block-storage-disk-snapshot.md).
## (Optional) Use secure copy (scp) to transfer files between instances
You can securely transfer files from your CentOS instance to the new AlmaLinux instance by using the secure copy command in Linux. For more information, see [Transfer files between Linux instances on Lightsail using scp](amazon-lightsail-transfer-files-between-linux-instances.md).
## (Optional) Move the block storage disk from the CentOS instance to the AlmaLinux instance
Use the following procedure to move a secondary block storage disk from your CentOS instance bundle to the AlmaLinux bundle. You cannot detach the instance's boot volume disk; the disk that contains the operating system. After you attach the disk to your AlmaLinux instance, you need to connect to that instance and mount the disk. For more information, see [Expand storage and performance with Lightsail block storage disks](elastic-block-storage-and-ssd-disks-in-amazon-lightsail.md).
If your CentOS instance is running, you will need to stop it before you can detach the disk. For more information, see [Stop a running instance](https://docs.aws.amazon.com/lightsail/latest/userguide/lightsail-how-to-start-stop-or-restart-your-instance-virtual-private-server.html#lightsail-instance-stop).
1. From the **Storage** section of the Lightsail console, select the disk that you want to detach from your CentOS instance.
1. On the **Details** tab, choose **Detach**.
1. From the disk **Details** page, choose the **Attach to an instance** dropdown menu. Then choose the name of your AlmaLinux instance.
1. Choose **Attach**.
1. (Optional) You might need to connect to your AlmaLinux instance and mount the disk before you can access its data. For more information, see [Connect to your instance to format and mount the disk](https://docs.aws.amazon.com/lightsail/latest/userguide/create-and-attach-additional-block-storage-disks-linux-unix.html#connect-to-linux-unix-instance-using-ssh-format-mount-disk).
**Warning**
The above link provides instructions for how to mount and format the attached disk. **Do not format the disk** that you attached to your AlmaLinux instance. Formatting it will permanently erase all information stored on the disk.