EVS Volumes

To meet data persistency requirements, CCI allows you to mount EVS volumes to containers. By using EVS disks, you can mount the file directory of a storage system to a container so that data in the volume is permanently preserved. Even if the container is deleted, only the volume is unmounted. Data in the volume is still stored in the storage system.

EVS supports three specifications: common I/O (previous-generation product), high I/O, and ultra-high I/O.

Common I/O (previous-generation product): The backend storage is provided by the SATA storage medium. It is perfect for high-capacity application scenarios with low read/write rate requirements and less transaction processing, such as scenarios involving development, testing, and enterprise office applications.
High I/O: The backend storage is provided by the SAS storage medium. It is perfect for application scenarios with relatively high performance, high read/write rate requirements, and real-time data storage requirements, such as scenarios involving file system creation and distributed file sharing.
Ultra-high I/O: The backend storage is provided by the SSD storage medium. It is perfect for application scenarios with high performance, high read/write rate requirements, and data-intensive requirements, such as scenarios involving NoSQL, relational database, and data warehouses (such as Oracle RAC and SAP HANA).

Constraints

EVS disks to be mounted are billed on a pay-per-use basis. For pricing details, see EVS Billing.
You cannot import the following EVS disks if they not in the current AZ, they are unavailable or frozen, or they are system disks, CCE-associated disks, non-SCSI disks, dedicated disks, or HANA server dedicated disks (high I/O performance optimization/ultra-high I/O latency optimization).
You can use an EVS volume only as a new disk. The content in the EVS volume that has not been mounted to CCI is invisible to the container.
If you delete an imported EVS disk from the EVS console, it cannot be detected by CCI. Therefore, delete the EVS disk after you confirm that it is not being used by any workload.
You can mount an EVS volume to only one pod. Otherwise, data may be lost.
EVS disk expansion is imperceptible to CCI. You need to unbind the EVS disk on the EVS page of the CCI console before the expansion, and import it again after the expansion is complete.

Adding EVS Disks

Log in to the CCI console. In the navigation pane on the left, choose Storage > EVS.
- If you have purchased EVS disks on the EVS console, go to 2.
- If you have not purchased any EVS disk, go to 3.
Click Import. On the Import EVS Disk page, select one or more EVS disks that you want to import and click Import.

You can import an EVS disk into one namespace only. After you import an EVS disk into a namespace, it will not be available for import in other namespaces. If you want to import an EVS disk that has its file system (ext4) formatted, ensure that no partition has been created for the disk. Otherwise, data may be lost.

After you import the EVS disk, you can see the corresponding volume.
Click Buy EVS Volume. On the displayed page, set the parameters, click Next, confirm the specifications, and click Submit.
- PVC Name: Enter the PVC name.
- Namespace: Select the namespace that the PVC belongs to.
- AZ: Specify the availability zone to which the disk belongs.
- Type: Specify the disk type, which can be common I/O (previous-generation product), high I/O, or ultra-high I/O.
- Capacity: The value range is 10 to 32768, in GiB.

Using EVS Volumes

After selecting a container in Creating a Deployment, expand Advanced Settings > Storage, click the EVS Volumes tab, and click Add EVS Volume.

You can mount EVS volumes only to workloads that contain one container.

After you create a workload, you can view the relationship between the EVS disk and the workload by choosing Storage > EVS.