tencent cloud

Overview

You can attach elastic cloud disks to a CVM instance in the same availability zone as a data disk. Up to 20 data disks can be attached to a CVM instance.

This document describes how to attach cloud disks to a CVM instance in the console and by using an API.

Note

Some Linux CVMs may not recognize an elastic cloud disk. You must first enable the disk hot swapping feature in the CVM. For more information, see Enabling the disk hot swapping feature.

Directions

Attaching cloud disks in the CBS console

1. Log in to the CBS console.
2. On the cloud disk list page, select and attach the cloud disks. Note that you can only attach cloud disks in To be attached status.

• Attach a single cloud disk: Find the target cloud disk, and click More > Attach under the Operation column.
• Attach multiple cloud disks: Select the cloud disks, and click Attach above the cloud disk list to attach them in a batch.

3. In the Attach to instance pop-up window, attach the disks to the instance.

Select the target instance, and complete the parameters Billing options.

• Unified expiry time with the instance (XXX)
• Enable monthly auto-renewal of the cloud disks (recommended)
• Attach directly

4. Click Next, and note the following in Subsequent operations:
   The cloud disk is offline after being manually attached. To use it, you need to log in to the instance to initialize it first.
5. Click Attach now.
   If the status of the cloud disk changes to Attached, the attachment is successful.
6. Perform the subsequent operations corresponding to different cloud disk capacities.

   Creation mode	Cloud disk capacity	Subsequent operations
   Manually created	Cloud disk capacity < 2 TB	Initializing cloud disks (< 2 TB)
   	Cloud disk capacity ≥ 2 TB	Initializing cloud disks (≥ 2 TB)
   Created from a snapshot	Cloud disk capacity = Snapshot capacity	Attach to Windows CVMs Log in to the instance, and go to Server Manager Storage Disk Management to make the disk online. Attach to Linux CVMs: Log in to the instance, and run the command mount , such as mount /dev/vdb /mnt, to make the disk usable.
   	Snapshot capacity < Cloud disk capacity ≤ 2 TB or 2 TB < Snapshot capacity < Cloud disk capacity	Attach to Windows CVMs: [Extending Partitions and File Systems (Windows)] Attach to Linux CVMs: [Extending Partitions and File Systems (Linux)]
   	Snapshot capacity ≤ 2 TB < Cloud disk capacity	If the snapshot uses a MBR partition, see Initializing cloud disks (≥ 2 TB) to repartition the disk with GPT. Note that this operation will delete the existing data If the snapshot uses a GPT partition, Attach to Windows CVMs: [Extending Partitions and File Systems (Windows)] Attach to Linux CVMs: [Extending Partitions and File Systems (Linux)]

Using the API to attach cloud disks

You can use the AttachDisks API to attach cloud disks. For more information, see AttachDisks.

Related Operations

Enabling the disk hot swapping feature

All existing images already support attaching and detaching elastic cloud disks. To detach a cloud disk, you must first run the umount command in Linux CVM or perform offline operations in Windows CVM. Otherwise, the reattached elastic cloud disk may not be recognized.

Note

Hot swapping is only recommended for CVMs with the following operating systems.

1. Log in to the Linux instance using Web Shell as the root user.
2. Run the following command to add the driver.

   modprobe acpiphp
   

3. (Optional) If you need to load the acpiphp module automatically after shutting down or re-starting the CVM, run the following command according to the operating system.
   • CentOS 5 Series
   • Debian 6 Series, Ubuntu 10.04 Series
   • openSUSE 12.3 Series

   1. Run the following command to create and open the acpiphp.modules file.
      

      vi /etc/sysconfig/modules/acpiphp.modules
      

   2. Add the following content to the file, and save it.
      

      #!/bin/bash
      modprobe acpiphp >& /dev/null
      

   3. Run the following command to grant execute permissions on the file.
      

      chmod a+x /etc/sysconfig/modules/acpiphp.modules
      

   1. Run the following command to modify the file.
      

      vi /etc/modules
      

   2. Add the following content to the file, and save it.
      

      acpiphp
      

   1. Run the following command to modify the file.
      

      vi /etc/sysconfig/kernel
      

   2. Add the following content to the file, and save it.
      

      MODULES_LOADED_ON_BOOT="acpiphp"
      

Attaching data disks automatically upon instance creation

If you specify a custom image and data disk snapshot while creating a CVM instance, the cloud disk created at the same time is automatically attached to the CVM and can be read and written without being initialized by partitioning, formatting and other operations. However, the specified custom images and data disk snapshots must meet the following requirements.

• Windows instances
• Linux instances

If you use a custom image to create a Windows CVM instance, the cloud disk created from the corresponding data disk snapshot will be automatically attached. The custom image and the data disk snapshot must meet the following requirements:

• The data disk must be formatted to ntfs or fat32 before you create a snapshot.
• The SAN policy in the custom image is onlineAll.

Checking configurations

Tencent Cloud provides pre-configured public images for Windows by default, but we still recommend that you perform the following steps to check configurations before creating a custom image. Please run the following commands in order and check the returned results.

diskpart

san

As shown below:

If you use a custom image to create a Linux CVM instance, the cloud disk created from the corresponding data disk snapshot will be automatically attached. The custom image and the data disk snapshot must meet the following requirements:

• The data disk must be formatted and attached to the source CVM.
• Add the following commands to the /etc/rc.local file to configure the mount point of the data disk before creating a system disk on the system disk.
  

  mkdir -p <mount-point>
  mount <device-id> <mount-point>
  

  
  

  Note

  • Replace <mount-point> with the mount point of the file system, such as /mydata.
  • Replace <device-id> with the partition path of the file system. For example, enter /dev/vdb if the file system has no partition, and /dev/vdb1 if the file system has partitions.