ECS snapshots can be billed on a pay-as-you-go basis. You are billed only after you create a snapshot.
- Snapshot size
The billing item of a pay-as-you-go snapshot. Unit: GiB.
The snapshot size is defined as the difference between the amount of storage space used by the current snapshot and that used by the last snapshot. You have a free storage quota of 5 GiB each month. Alibaba Cloud identifies disk space that has never been written to and marks it as an empty block to reduce the amount of space for which you are billed. Therefore, the size of a single incremental snapshot is smaller than the disk size. For more information, see Snapshot concepts.
- Snapshot storage duration
The number of hours from the time when a snapshot is created to the time when it is deleted. Alibaba Cloud updates billing data and bills pay-as-you-go resources every hour. At the time of billing, you are billed for an entire hour even if your snapshot is stored for less an hour.
- Snapshot unit price
The price per GiB for snapshot storage is the same as that for the OSS Standard storage class and is billed on a monthly basis. For a list of snapshot prices by Alibaba Cloud region, click the Pricing tab on the Elastic Compute Service page. Scroll down to the Snapshot Fee section to view the price list based on the region. You can also download the list of snapshot prices by Alibaba Cloud region in CSV or JSON format by clicking Download price.
Example of pay-as-you-go snapshot billing
One day Alex created three snapshots that were 50, 220, and 40 GiB in size in the China (Hangzhou) region for the first time at 10:20. The fees for the three snapshots during the period from 10:20 to 11:00 are calculated as follows:
- Snapshot size: 50 GiB + 220 GiB + 40 GiB = 310 GiB.
- Snapshot storage duration: The duration from 10:20 to 11:00 is less than an hour but it is billed as a full hour.
- Snapshot unit price: In this example, assume that the price for a snapshot in the China (Hangzhou) region is USD 0.0200/GiB/month, which is equivalent to USD 0.0000277778/GiB/hour.
After the free storage quota of 5 GiB per month is deducted, Alex needs to pay the following snapshot fee: (310 - 5) GiB × USD 0.0000277778/GiB/hour × 1 hour = USD 0.008472.
- The actual payable amount shown on the billing page is USD 0.008.
- However, the billing history records it as USD 0.0085.
If your payment account balance in the current billing cycle is less than the payable amount of the previous billing cycle, the system sends an SMS or email notification. The snapshot service is suspended 24 hours after the bill becomes overdue. From the day the bill becomes overdue:
- In the first 15 days, all existing snapshots are retained, but no snapshots can be created. All automatic snapshots whose retention period is less than 15 days are deleted.
- After 15 days, all snapshots are deleted, except for those that have been used to create disks or custom images. The automatic snapshot policy is also deleted.