See the following table for the disks provided by ECS.

Name Code Maximum capacity per disk (GiB) Volume limit per instance Maximum capacity of disks allowed per instance (GiB)
Basic disk cloud 2000 17 2000 * 17
Ultra disk cloud_efficiency 32768 17 32768 * 17
Standard SSD cloud_ssd 32768 17 32768 * 17
Enhanced SSD (ESSD) essd 32768 17 32768 * 17

For more information, see Block storage performance.