Use Limits on Cloud Disk
Item | Description |
Enhanced SSD usage | Currently, Enhanced SSD is only available in certain AZs and will be supported in more AZs in the future. You can check the information on the purchase page. Enhanced SSDs can only be mounted on new generation instances such as S5, M5, SA2, and above, created after August 1, 2020 (for example, for standard instances, series not lower than the fifth generation like S5, S6 are supported). When mounted on older generation instances, the promised performance cannot be guaranteed. Enhanced SSD cannot be used as the system disk. Enhanced SSD cannot be encrypted. Enhanced SSD cannot be upgraded from other disk types. |
ulTra SSD usage | Currently, ulTra SSD is only available in certain AZs and will be supported in more AZs in the future. You can check the information on the purchase page. Ultra-fast SSD cloud disks can only be purchased in conjunction with the S5se instance type. ulTra SSD cannot be purchased independently. ulTra SSD cannot be used as the system disk. ulTra SSD cannot be encrypted. ulTra SSD cannot be upgraded from other disk types. |
Elastic cloud disk capability | Since May 2018, all data disks purchased with CVMs are elastic cloud disks, which can be detached from and reattached to CVMs. This feature is supported in all availability zones. |
Cloud disk performances | I/O performance is effective simultaneously. For instance, a 1TB SSD cloud disk can reach a maximum random IOPS of 26,000, which means both read IOPS and write IOPS can achieve this value. However, due to multiple performance constraints, in this case, I/O with a block size of 4KB/8KB can reach the maximum IOPS, but I/O with a block size of 16KB cannot reach the maximum IOPS (as the throughput has already reached the limit of 260MB/s). |
Max attachable elastic cloud disks per CVM | Up to 20. |
Number of cloud disks created at a time | Up to 50. |
Limits on the number of instances to which a cloud disk can be attached | Cloud disks and instances (CVM or Lighthouse instances) to which they are attached must be in the same AZ. The Cloud Disks of CVM instances and the Cloud Disks of Light Cloud instances are independent of each other. A Cloud Disk of a CVM instance cannot be attached to a Light Cloud instance, and vice versa. |
Releasing overdue cloud disks | If a monthly subscription elastic cloud disk is not renewed within 7 days after its expiration, the system will forcibly unmount the disk from the cloud server and recycle it to the recycle bin. For specific recycling mechanisms, please refer to the Arrears Description. At present, when a monthly subscribed elastic cloud disk is attached to a monthly subscribed cloud server, you can choose the following renewal methods based on your actual needs: Unified expiry time with the CVM Enable monthly auto-renewal of the cloud disks Attach directly without enabling auto-renewal |
Use Limits on Snapshot
Item | Description |
Supported disk type | You can only use the data disk snapshot to create elastic cloud disks, while using the system disk snapshot to create a custom image. |
Capacity of cloud disk created using a snapshot | The capacity of the cloud disk created using a snapshot should be greater than or equal to that of the snapshot. |
Snapshot rollback | Snapshots can only be rolled back to the original cloud disk from which they were created. If you wish to create a new cloud disk using an existing snapshot, please refer to Create Cloud Disk from Snapshot. |
Total snapshot size | No limit. |
Snapshot quota in one region | 64 + the number of cloud disks in the region * 64. |
Use Limits on Scheduled Snapshot Policy
Item | Description |
Scheduled snapshot policy quota in one region | A single Tencent Cloud account can set a maximum of 32 scheduled snapshot policies in each region. |
Number of scheduled snapshot policies being associated with one cloud disk | A cloud disk can associate with a maximum of 10 scheduled snapshot policies in the same region. |
Number of cloud disks associated with one scheduled snapshot policy | A scheduled snapshot policy can be associated with a maximum of 200 cloud disks in the same region. |