How to understand the difference between independent cloud disks and availability zones FAQ-Linux Operation and Maintenance-php.cn

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Independent cloud disk and availability zone FAQ

What is an independent cloud disk?

Independent cloud disk refers to a cloud disk that can exist independently relative to cloud server ECS. It can be freely mounted and unmounted between different ECS instances in the same availability zone, and cannot cross regions. , Mount across availability zones. The basic characteristics of independent cloud disks are the same as cloud disks, and the data reliability is the same as cloud disks. Compared with cloud disks, independent cloud disks take into account both data security and the flexibility of ECS instance disk changes.

What is an availability zone?

An availability zone refers to a physical area in the same region where power and network are independent of each other. Failures will be isolated in an availability zone. In the same region, intranets are interconnected between Availability Zones, and the network latency of ECS instances in the same Availability Zone is smaller; faults are isolated between different Availability Zones, and independent cloud disks can be stored between different ECS instances in the same Availability Zone. Freely mount and unmount.

If your application requires higher high availability, it is recommended that you create ECS instances in different availability zones.

What is the difference between independent cloud disks and current disks?

Temporary disks and cloud disks are generated directly when the instance is purchased and cannot be uninstalled. Independent cloud disks can be purchased separately and mounted on the instance. Once mounted, use the temporary disk and the temporary disk. There is no difference from cloud disk.

What is the relationship between server application and availability zone selection?

If your application requires higher high availability, it is recommended that you create ECS instances in different availability zones. If you need lower network access latency between ECS instances, it is recommended that the ECS instances be created in the same availability zone. Independent cloud disks can only be mounted on ECS instances in the same availability zone

Can an independent cloud disk be mounted on multiple ECS instances?

cannot. An independent cloud disk can only be mounted to one instance in the same Availability Zone at the same time, and cannot be mounted across Availability Zones.

How much do independent cloud disks cost?

Independent cloud disks are charged based on volume. If the account balance is insufficient, the independent cloud disk service will be stopped.

Can an independent cloud disk be mounted to a subscription instance?

Yes, independent cloud disks can be mounted to any instance in the same availability zone in the same region, including annual and monthly subscription and pay-as-you-go instances.

Is the disk performance and data security of independent cloud disks and ordinary cloud disks the same? Will the disk performance be improved?

Independent cloud disks are the same as ordinary cloud disks Yes, there is no difference and there will be no improvement in disk performance.

Can I uninstall the unnecessary disks on my subscription instance?

Not available for now.

Why are my independent cloud disks released together with my instance?

When mounting an independent cloud disk, you can decide whether the disk will be released with the instance or retained when the instance is released. The system will execute it based on your choice. Of course you can change this option at any time via the console and API.

Why can’t I find the instance I want to mount when mounting an independent cloud disk?

Please ensure that your instance and disk are in the same availability zone in the same region. Independent cloud disks can only be mounted in the same availability zone in the same region, or ensure that your instance Not released.

Why can’t I find the disk I want to mount when I select an independent cloud disk to mount in the instance list?

When I delete the disk, will the snapshot be retained?

Manual snapshots will not be deleted, but whether automatic snapshots will be deleted depends on related configurations. Please refer to Automatic Snapshots Released with Disk.

Why is there no automatic snapshot of my independent cloud disk?

The independent cloud disk will only execute the policy of creating new automatic snapshots when it is in use (when mounted to an instance), but the original automatic snapshots will be gradually deleted over time. delete.

Why can’t I buy an independent cloud disk?

Because you currently do not have the permission to purchase and use independent cloud disks, you can submit an application through a work order, and we will gradually enable it for you.

How many independent cloud disks can be mounted on one instance?

Each instance (including annual subscription and pay-as-you-go) can have up to 16 data disks, including all disk types.

When I uninstall an independent cloud disk, will my disk lose data?

Strongly recommended:

Under the Windows operating system, in order to ensure data integrity, it is recommended that you suspend read and write operations on all file systems of the disk, otherwise the read and write operations will not be completed. data will be lost.

Under the Linux operating system, you need to log in to the instance and perform the unmount command line operation on the disk. After the command is successfully executed, enter the console to "unmount" the disk.

Can my system disk be uninstalled?

No, but it can be replaced. See Replacing the System Disk.

What is a device name?

The device name is the location of the disk on the Alibaba Cloud server on the disk controller bus. The selected device name corresponds to the disk device number in the Linux environment; in the Windows environment, it is consistent with the disk sequence in the disk manager.

Why can’t I find the operations to reset the disk, change the operating system, and roll back the snapshot on the console?

Currently these functions have been changed to: reinitializing the disk, replacing the system disk and rolling back the disk.

Will my snapshots be lost when reinitializing the disk?

Won't. Neither manual nor automatic snapshots are lost.

Will my snapshots be lost when I replace the system disk?

Won't. However, please note that replacing the system disk is equivalent to replacing your system disk. The disk ID will change, and the snapshots (manual snapshots and automatic snapshots) of your original system disk cannot be used to roll back the new system disk. The user snapshot of the original system disk is still retained (automatic snapshots will be deleted), and custom images can be created.

Why can’t I select a temporary disk for my data disk?

Only when the system disk is a temporary disk, you can select a temporary disk and a cloud disk. If the system disk is a cloud disk, you can only select the data disk. Cloud disk.

What are the application scenarios of independent cloud disk servers?

Mainly used for fast data transfer and data storage between different instances.

Can I use user snapshots to create independent cloud disks?

Select an existing snapshot to directly create an independent cloud disk. The newly created independent cloud disk has the same capacity and data as the snapshot, and the capacity cannot be changed.

After purchasing an independent cloud disk and mounting it to the mount point of the target instance, do I still need to perform the disk mounting operation?

After the "Disk Mount" is successfully executed, you still need to log in to this instance to perform "partition formatting and mounting new partitions" on the mounted disk. For the tutorial, refer to Mounting a Data Disk.

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