ENS disks are block-level storage resources for Edge Node Service (ENS) instances, providing low latency, high performance, high durability, and high reliability. A distributed triplicate mechanism stores three replicas of your data across a storage cluster, providing at least 99.9999% (6 nines) data reliability.
This topic covers independently created disks only. System disks and data disks created together with an ENS instance share the instance's lifecycle and are not included here.
Disk types
ENS disks are classified by performance (ultra disk, all-flash disk) and by usage (system disk, data disk).
| Dimension | Disk type | Description |
|---|---|---|
| Performance | Ultra disk | Cost-effective disks with medium random IOPS and high data reliability. |
| All-flash disk | High-performance disks with consistent high random IOPS and high data reliability. | |
| Usage | System disk | Contains the operating system. Created only together with an ENS instance; its lifecycle is tied to the instance. |
| Data disk | Stores application data. Can be created separately or together with an ENS instance. |
Limits
| Item | Limit |
|---|---|
| Maximum system disks per instance | 1 |
| Maximum data disks per instance | 15 (including data disks created together with the instance) |
| Ultra disk capacity | 20 GiB–32,768 GiB |
| All-flash disk capacity | 20 GiB–32,768 GiB |
Data security
Read/write stability
Three replicas of your data are stored in a storage cluster on a node. This distributed triplicate mechanism ensures at least 99.9999% (6 nines) data reliability during read and write operations.
Data deletion
When you delete data, it is cleared from the distributed storage system and cannot be accessed by other users. When a disk is released:
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The storage system destroys the disk's metadata, making the data inaccessible.
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The physical storage space is recycled and cleared before being re-assigned.
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Until data is written to the new disk, all read requests return zero.
Billing
Independently created disks use the pay-as-you-go billing method. Disks created together with an ENS instance use the same billing method and lifecycle as that instance. For current prices, see the buy page.
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Billing method |
Billing conditions |
Formula |
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Subscription (created with a subscription instance) |
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Cost = Disk capacity × Monthly unit price of the disk × Subscription duration |
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Pay-as-you-go (includes independently created disks and disks created with a pay-as-you-go instance) |
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Cost = Peak disk capacity of the month × Monthly unit price of the disk × Validity factor Note
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