Planning the Expansion

Specifying the Type and Number of the Disks to Be Added

• After selecting the disks to be added, record the type and specifications of the disks in a list to facilitate verification before hardware installation and to prevent a capacity expansion failure due to type or specification incompatibility.

• For a disk domain that has services running, the disk domain automatically starts the balancing policy after a disk is added. After the balancing policy starts, the added disk cannot be deleted from the disk domain.

Comply with the following rules when adding disks:

• The disks to be added must be of the same type as the disks supported by disk enclosures.
• The disks to be added must be of the same type as the disks in the storage tier to be expanded.
• It is recommended that the capacity of added disks be the same as the disk capacity at the storage layer that requires capacity expansion.
  • If the capacity of added disks is larger than the disk capacity at the storage layer that requires capacity expansion, you are advised to create a disk domain for the new disks. Otherwise, the capacity of new disks may not be fully utilized, wasting capacity, or the new disk performance could become the bottleneck.
  • If the capacity of added disks is smaller than the disk capacity at the storage layer that requires capacity expansion, capacity expansion may fail.
  • The RAID policy is set to RAID 6 when the capacity tier consists of NL-SAS disks.
• The disks to be added must be of the same rotating speed as the disks in the storage tier to be expanded.

For the disk types and specifications supported by the storage system, refer to the Specifications Query Assistant (https://support-it.huawei.com/spec/#/home).

Determining the Number of the Disks to Be Added

After determining the disk types and models, ask your service provider to recommend the planned expansion capacity, estimate the capacity of each disk to be added, calculate the allowed expansion capacity, and calculate the capacity used by the file system. Then compare your calculated capacity and the capacity provided by the service provider.

Ensure that the planned expansion capacity provided by your service provider is equal to or smaller than the allowed expansion capacity minus capacity used by the file system.

Then, divide the planned expansion capacity by the capacity of a disk to obtain the number of disks to be added.