Guide to creating and using system disks - Elastic Compute Service

Alibaba Cloud cloud disks provide persistent storage for Elastic Compute Service (ECS) instances. You can attach cloud disks to ECS instances as system disks, which store operating system-related data and play a crucial role in the operation of the instances. This topic describes the common operations that you can perform on system disks.

Common operations

The following figure shows the common operations that you can perform on a system disk during the lifecycle of the disk.

Create a system disk

You can create a system disk only when you create an ECS instance. You can cannot separately create a system disk. The system disk is automatically initialized when you create the ECS instance. For information about how to create an ECS instance, see Create an instance on the Custom Launch tab.

Note

You can use a cloud disk created from a system disk snapshot only as a data disk.

Operate and maintain a system disk

Scenario	References
View the basic information and monitoring data of a system disk.	Query the serial numbers of block storage devices View the monitoring data of a cloud disk
Use snapshots to back up and restore data on a system disk.	Create a snapshot Roll back a cloud disk by using a snapshot
Upgrade the specifications of a system disk based on your business requirements.	Change the category of a disk Change the performance level of an ESSD Modify the performance configurations of an ESSD AutoPL disk
Extend the storage capacity of a system disk based on your business requirements.	Step 1: Resize a disk to extend the capacity of the disk Step 2: Extend partitions and file systems on a system disk Extend the partitions and file systems of disks on a Linux instance Extend the partitions and file systems of disks on Windows instances
Re-initialize a system disk to restore the disk to its initial state.	Re-initialize a system disk (reset the operating system)
If the system disk of an ECS instance is damaged, you can detach the disk, repair the disk, and then re-attach the disk to the instance.	Detach or attach a system disk
If you want to use a different operating system, you can change the operating system of an ECS instance by replacing the system disk.	Replace the system disk (operating system) of an instance
Modify the tags of a system disk and search for and manage the disk based on the tags.	Modify the tags of a disk

Release a system disk

You can release system disks only together with ECS instances. The Release Disk with Instance feature is automatically enabled for system disks when you create the disks.

Scenario

References

If you no longer use the system disk of an ECS instance, you can release the instance to release the system disk.

Create a snapshot

Release an instance

If you want to release an ECS instance and retain the system disk of the instance, you can disable the Release Disk with Instance feature for the system disk and then release the instance. This way, the system disk is automatically detached and retained as a data disk when you release the ECS instance.

Enable the Release Disk with Instance feature

References

For information about how to clean up system disks on a regular basis, see Use OOS to periodically clean up disk space.

For information about how to move business data from a system disk to a data disk, see How do I use a data disk to store the business data on the system disk of a Linux ECS instance?