Creating a Block Storage Pool

Context

• You have installed storage nodes.
• A storage pool can contain only one type of main storage disks. Different storage pools must be planned for different types of main storage disks.
• It is recommended that all the storage nodes to be added to a storage pool have the same number of main storage disks. Otherwise, the difference in the number of main storage disks on each storage node cannot exceed 2 or 33%.
• It is recommended that main storage disks in the same storage pool have the same capacity. Otherwise, the system uses all disks as they have the capacity same as the disk with the smallest capacity in the storage pool.
• The type and number of cache disks in the same storage pool must be the same. Different types of cache media must be planned with different resource pools.
• You are advised to configure no more than 32 nodes for each disk pool. If the number of nodes exceeds 32, divide them into multiple disk pools. In this case, it is recommended that the number of nodes in each disk pool be the same. For example, if there are 90 nodes, you are advised to divide them into three disk pools. Each disk pool contains 30 nodes.
• The total capacity of cache disks on a single storage node to be added to a storage pool must be greater than Max. Main Storage Media per Node x 40 GB.
• For a single node to be added to a storage pool, the percentage of its cache capacity divided by its main storage capacity must be greater than or equal to 2%. It is recommended that the percentage be greater than 4%.
• The planned capacity of a storage pool must be greater than the expected size of data to be stored in the storage pool to reserve space for storing data that has been overwritten or deleted but for which garbage collection has not been performed. This may depend on the service model and load (in extreme cases, the excess may reach 6% of the storage pool capacity).

Procedure

1. Choose Resources > Resources > Storage Pool.
2. Click Create.

   The Create Storage Pool page is displayed.

3. Configure basic information for the storage pool.

   Table 1 describes related parameters.

   Table 1 Storage pool parameters

   Parameter	Description
   Storage Pool Name	Name of the storage pool. NOTE: The name must be unique. The name can contain only letters, digits, underscores (_), and hyphens (-). The name contains 1 to 64 characters.
   Storage Pool ID	ID of the storage pool. [Value range] 0 to 127
   Service Type	Service type of the block storage pool.
   Storage Pool Type	Type of the storage pool. Possible options are Common and Self-encrypting. You are advised to select Common. If you have high requirements on data security, select Self-encrypting. Common: This type of storage pools does not support data encryption. Self-encrypting: This type of storage pools supports data encryption. NOTE: Only the license of the advanced edition supports the creation of self-encrypting storage pools.
   Key Service	Internal key service: The built-in key management function of the system is used. External key service: An external key management server is used. If you select this option, you need to configure the external key service first. For details, see Managing the External Key Service. NOTE: This parameter is available only when you select a key management service during the creation of a self-encrypting storage pool.
   Redundancy Policy	Redundancy policy of the storage pool. Possible options are EC and Data copy. In consideration of performance and reliability, EC is recommended. EC: Data redundancy protection is implemented by calculating parity fragments. Data copy: Multiple copies of the same data are stored on different nodes for data protection.
   Main Storage	Main storage type of the storage pool. When Storage Pool Type is set to Common, the value of this parameter can be SAS, Self-encrypting SAS, SATA, Self-encrypting SATA, SSD, and SSD card or NVMe SSD. In this case, self-encrypting drives function as common disks and do not use the encryption function. When Storage Pool Type is set to Self-encrypting, the value of this parameter can be Self-encrypting SAS, Self-encrypting SATA, Self-encrypting SSD card or NVMe SSD (with Chinese cryptographic algorithms), or Self-encrypting SSD card or NVMe SSD (with international cryptographic algorithms). Each node must be configured with at least four disks of the same type. NOTE: Meanings of the values are: SAS: SAS HDDs SATA: SATA HDDs SSD card or NVMe SSD: NVMe SSDs SSD: SAS SSDs
   Cache	Cache type of the storage pool. NOTE: This parameter is not required when Main Storage is set to SSD or SSD card or NVMe SSD. Meanings of the values are: SSD card or NVMe SSD: NVMe SSDs SSD: SAS SSDs
   Data Copies	Number of redundant data copies allowed by the storage pool. NOTICE: When Security Level is set to Cabinet and the number of cabinets is 3, Data Copies is set to 3, and the capacities of cabinets are different (the number of nodes or disks in each cabinet is different), the storage pool has unavailable space. In this case, you are advised to re-plan the number of cabinets or nodes to avoid unavailable space in the storage pool. For example, if the number of cabinets is 3, the number of copies is 3, and the number of nodes is 13 (the number of nodes in each cabinet is 4, 4, and 5, and the capacities are different), the preceding problem occurs. In this case, you need to add two nodes or one cabinet. NOTE: This parameter is available only when Redundancy Policy is set to Data copy.
   Hot Spare Space (%)	Hot spare space is the space reserved in the system to take over data from faulty disks. This improves reliability and avoids system redundancy reduction. To support data rebuilding after single-disk failure at high capacity usage, the recommended value is (1/Number of disks on a single node) x 100%. [Value range] 0 to 25 [Default value] 0 NOTE: Reserving too much hot spare space will occupy excessive available system capacity, causing the available capacity obtained by users to decrease. Configure the hot spare space properly.

4. Create a disk pool.
   1. In the Disk Pool area, click Create.

      The Create Disk Pool page is displayed.

   2. Set basic parameters for the disk pool. Table 2 describes related parameters.

      Table 2 Disk pool parameters

      Parameter	Description
      Disk Pool Name	Name of the disk pool. NOTE: The name must be unique. The name can contain only letters, digits, underscores (_), and hyphens (-). The name contains 1 to 64 characters.
      Security Level	Security level of the disk pool. Possible options are Node and Cabinet. Node: N+M: N data fragments and M parity fragments are randomly stored on different nodes. (The number of storage nodes is greater than N + M. To ensure reliability, data fragments are stored on different nodes.) In this case, the disk pool can tolerate the failure of M disks or M nodes simultaneously. N+M:1 (folded): N data fragments and M parity fragments are randomly distributed on all nodes. Each node stores M fragments. In this case, the disk pool can tolerate the failure of M disks simultaneous or one node. Cabinet: N data fragments and M parity fragments are stored in different cabinets. If M cabinets, M nodes, or M disks are faulty, the system can still read and write data properly without service interruption or data loss. N+M: N data fragments and M parity fragments are randomly stored in different cabinets. (The number of storage nodes is greater than N + M. To ensure reliability, data fragments are stored in different cabinets.) In this case, the disk pool can tolerate the failure of M cabinets, M disks, or M nodes simultaneously. N+M:1 (folded): N data fragments and M parity fragments are randomly distributed in all cabinets. Each cabinet stores M fragments. In this case, the disk pool can tolerate the failure of one cabinet.
      EC	EC redundancy policy of the disk pool. Select the EC redundancy ratio planned in the Bill of Quotation (BOQ). NOTICE: When Security Level is set to Cabinet, the number of cabinets is less than or equal to N + M, the remainder of (N + M)/Number of cabinets is 0, and the capacities of cabinets are different (the numbers of nodes or disks in each cabinet are different), the storage pool has unavailable space. In this case, you are advised to re-plan the number of cabinets or nodes to avoid unavailable space in the storage pool. For example, if the number of cabinets is 4, the EC redundancy ratio is 6+2, and the number of nodes is 15 (the numbers of nodes in each cabinet are 4, 4, 4, and 3, and the capacities are different), the preceding problem occurs. In this case, you need to add one server or one cabinet. When Security Level is set to Cabinet, ensure that the number of cabinets is not equal to (N + M). Otherwise, if a single node in a cabinet is removed due to a fault, the capacity of the entire storage pool will be greatly reduced. For example, when the number of cabinets is 6, the EC redundancy ratio is 4+2, and the number of nodes in each cabinet is 3, if the used capacity of each main storage disk is less than 60% of the total capacity and a node in a cabinet is removed due to a fault, the total capacity of the storage pool will decrease by 1/3. NOTE: This parameter is available only when Redundancy Policy is set to EC. When creating multiple disk pools, ensure that the settings of Parity Fragments for the disk pools are the same.
      Max. Main Storage Media per Node	Maximum number of main storage disks that can be used on a single storage node to store user data. The value of this parameter determines the allocation of cache and compute resources on the node. Set this parameter based on site requirements. To ensure that cache resources can be allocated to newly added main storage disks in the case of capacity expansion, you are advised to set this parameter based on the total number of main storage disks after capacity expansion. If the value is too small, newly added main storage disks cannot be allocated with cache resources. Cache resources can be allocated to newly-added main storage disks only after both main storage disks and cache disks are added. If the value is too large, extra cache resources are reserved. As a result, cache resources cannot be fully utilized to improve read/write performance. If you select Self-adaptive, the system automatically determines the value based on the number of selected main storage disks. Assume that the number of selected main storage disks is N: If 4 ≤ N ≤ 12, a single node supports a maximum of 12 main storage disks. If 12 < N ≤ 24, a single node supports a maximum of 24 main storage disks. If N = 25, a single node supports a maximum of 25 main storage disks. If 25 < N ≤ 36, a single node supports a maximum of 36 main storage disks. Ensure that the total capacity of the cache disks on selected storage nodes is greater than the maximum number of main storage disks on a single node multiplied by 40 GB. If you select Custom, set the value based on site requirements. The value ranges from 4 to 60.

   3. In the Choose Node and Disk area, select the nodes and disks that are used to create the disk pool.
      

      • You can click Add and add nodes and disks in the cluster to the disk pool on the Choose Node and Disk page that is displayed.
      • You can select one or more added nodes or disks and click Remove to remove them.
   4. Click OK and confirm your operation as prompted.

5. Click Create.
6. Confirm your operation as prompted.
   

   After the storage pool is created, the system automatically creates VBSs for nodes in the storage pool. You can choose Monitor > Task Center to view the creation progress.