Provision cloud disk volumes statically or dynamically in ACK clusters via the CSI plugin.
Disk types
Choose a disk type based on your IOPS and workload requirements.
| Type | Architecture | Max IOPS | Recommended for |
|---|---|---|---|
| Enhanced SSD (ESSD) | Next-generation distributed block storage with 25 Gigabit Ethernet and remote direct memory access (RDMA) | 1,000,000 | Online transactional processing (OLTP) databases, NoSQL databases, ELK (Elasticsearch, Logstash, and Kibana) distributed logs |
| Standard SSD | High-performance disk with consistent random IOPS | — | I/O-intensive applications, small to medium relational databases, NoSQL databases |
| Ultra disk | Cost-effective disk with medium random IOPS | — | Development and testing environments (system disks) |
| Basic disk | Previous-generation disk | — | Unavailable for purchase |
All disk types deliver low latency and high reliability through a distributed triplicate mechanism. If an unexpected hardware failure occurs, data is automatically recovered from the other replicas within the zone.
For detailed performance specifications such as throughput and IOPS limits per disk size, see EBS performance.
Limitations
Review these constraints before provisioning a disk volume.
Workload type
Mount disks using a StatefulSet, not a Deployment. Deployments do not guarantee mount and unmount order—a new pod may start before the disk is unmounted, causing mount failures. If you must use a Deployment, set the replica count to 1.
Node and disk limits
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Each node supports up to 16 mounted disks.
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Each disk has a maximum capacity of 32 TiB.
Disk and instance compatibility
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The disk type must match the ECS instance type in your cluster. See Overview of instance families for compatibility rules.
Use cases
Mount a disk volume using one of these provisioning approaches:
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Use a statically provisioned disk volume — attach a pre-existing disk by creating a PV manually.
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Use a dynamically provisioned disk volume — let the CSI plugin provision a disk automatically when a PVC is created.
Billing
Only pay-as-you-go disks can be mounted to an ACK cluster. If you change an ECS instance's billing method from pay-as-you-go to subscription, do not change the attached disk's billing method to subscription — doing so prevents the disk from being mounted to the cluster.
For pricing details, see the ECS product page and Billing.