A storage plan offsets the storage costs of pay-as-you-go instances in the region where the plan is purchased.
How storage plans offset costs
After you purchase a storage plan, ApsaraDB for MyBase automatically measures the storage used by pay-as-you-go instances in the same region every hour and applies the plan against those costs. The plan continues to offset storage costs until it expires. If your usage exceeds the plan capacity, the excess is charged at pay-as-you-go rates.
View hourly offset records in the Billing Management console.
Offset factors
The effective coverage of a storage plan depends on two factors: the Enhanced SSD (ESSD) performance level (PL) and the instance edition. Each combination has a different effective cost per TB consumed from the plan.
| Storage type | Basic Edition | High-availability Edition |
|---|---|---|
| PL1 ESSD | 1× (full capacity) | 2× (half capacity) |
| PL2 ESSD | 2× (half capacity) | 4× (quarter capacity) |
| PL3 ESSD | 4× (quarter capacity) | 8× (one-eighth capacity) |
How to read this table: The multiplier shows how many plan units each TB of storage consumes. A 10 TB plan with a 2× multiplier covers 5 TB of actual storage.
The multipliers are derived from these base offset factors:
| Storage type | Base offset factor | Basic Edition multiplier | High-availability Edition multiplier | Effective cost per TB |
|---|---|---|---|---|
| PL1 ESSD | 1 | ×1 | ×2 | 1 (Basic) / 2 (HA) |
| PL2 ESSD | 2 | ×1 | ×2 | 2 (Basic) / 4 (HA) |
| PL3 ESSD | 4 | ×1 | ×2 | 4 (Basic) / 8 (HA) |
Examples
The following examples use a 10 TB storage plan.
Scenario 1: Plan fully covers a Basic Edition instance
A 10 TB plan fully covers a Basic Edition instance up to the following storage limits:
| Storage type | Maximum coverage |
|---|---|
| PL1 ESSD | 10 TB |
| PL2 ESSD | 5 TB |
| PL3 ESSD | 2.5 TB |
Scenario 2: Plan covers less storage on a High-availability Edition instance
High-availability Edition instances use a 2× edition multiplier, so the same 10 TB plan covers less storage:
| Storage type | Maximum coverage |
|---|---|
| PL1 ESSD | 5 TB |
| PL2 ESSD | 2.5 TB |
| PL3 ESSD | 1.25 TB |
Scenario 3: Plan covers a Basic Edition instance with mixed ESSD types
For a Basic Edition instance with multiple ESSDs of different performance levels, the plan offsets the combined cost. A 10 TB plan fully covers either of the following combinations:
-
PL1 ESSDs totaling 10 TB
-
PL3 ESSDs totaling 1 TB + PL2 ESSDs totaling 2 TB + PL1 ESSDs totaling 2 TB
The second combination consumes (1 × 4) + (2 × 2) + (2 × 1) = 10 plan units, which exactly matches the 10 TB plan.