Manage disk pools
A disk pool is a group of disks that are located on the same host or different hosts. You can assign disks to disk pools based on their performance to resolve disk compatibility issues about heterogeneous servers. The system saves replicas or blocks of data in a specified disk pool for high availability. The data is available as long as the number of failed disks does not exceed the limit specified in the redundancy policy of the disk pool.
Restrictions and guidelines
You must create disk pools after the system is initialized. You can create a maximum of five disk pools.
You cannot delete a disk pool when it is in use.
Services might be interrupted if you set the restore policy to Reconstruction First. As a best practice, select Reconstruction First only when the service load is low.
Add a disk pool
On the top navigation bar, click Cloud Resources, and then select Storage > Distributed > Disk Pools from the navigation pane.
Click Add.
Configure the parameters as described in "Parameters."
Click OK.
Edit a disk pool
On the top navigation bar, click Cloud Resources, and then select Storage > Distributed > Disk Pools from the navigation pane.
Select a disk pool, and then click Edit.
Configure the parameters as described in "Parameters."
Click OK.
Delete a disk pool
On the top navigation bar, click Cloud Resources, and then select Storage > Distributed > Disk Pools from the navigation pane.
Select a disk pool, and then click Delete.
Click OK in the dialog box that opens.
Configure a disk pool
On the top navigation bar, click Cloud Resources, and then select Storage > Distributed > Disk Pools from the navigation pane.
Select a disk pool, and then click the
icon.
Assign disks to the disk pool, and then click Next.
Click Finish.
View disk information about a disk pool
On the top navigation bar, click Cloud Resources, and then select Storage > Distributed > Disk Pools from the navigation pane.
Select a disk pool, and then click the
icon.
Click OK to return to the disk pool list.
Parameters
Service Type: Select the storage service that the disk pool provides.
When you select block storage as the service type, configure the following parameters:
Restore Policy: Select a traffic rate for data balancing. The options are ordered from highest rate to lowest as follows: Reconstruction First, Self-adaptive, Service First.
Provisioning: Select a volume provisioning mode. This parameter determines how space is allocated to the block devices created in a data pool that uses this storage pool and whether resource overcommitment is allowed.
Thick—Allocates the specified maximum storage space to a block device when the block device is created. The capacity of a block device in a data pool cannot exceed the available capacity of the data pool.
Thin—Allocates space to a block device on demand. The capacity assigned to a block device when it is created can exceed the available capacity of the data pool.
Deployment Mode: Select a deployment mode.
SSD Caches+HDDs—Deploy HDDs as data disks and deploy SSDs as read or write caches.
All SSDs—Deploy SSDs as data disks. Use this mode to provide high-performance storage. In this node, no read or write caches are used.
All HDDs—Deploy HDDs as data disks without read or write caches. Use this mode to provide regular storage services.
Cache Size: Set the cache size. This parameter is available only when you select the SSD Caches+HDDs deployment mode. The system divides SSDs into partitions based on the number of data disks and assigns a partition to each data disk as its cache. The default cache size is 50 GB. You can increase the cache size if the amount of service data is large.
When you select file storage, file storage-data pool, or file storage-metadata pool as the service type, configure the following parameters:
Acceleration Method: Select an acceleration method. This parameter is available only when the service type is file storage or file storage-data pool. If you select Cache Disk, you must add cache disks and data disks to the disk pool. Data read and write is accelerated by high-speed cache disks.
Restore Policy: Select a traffic rate for data balancing. The options are ordered from highest rate to lowest as follows: Reconstruction First, Self-adaptive, Service First.
Data Disk Type: Select the type of disks for storing data. Only disks of the specified type can be added to the disk pool.
Cache Disk Type: The cache disk type can only be SSD. This parameter is configurable only when the service type is file storage or file storage-data pool and the acceleration method is cache disk.
When you select object storage, object storage-data pool, or object storage-metadata pool as the service type, configure the following parameters:
Restore Policy: Select a traffic rate for data balancing. The options are ordered from highest rate to lowest as follows: Reconstruction First, Self-adaptive, Service First.
Deployment Mode: Select a deployment mode.
SSD Caches+HDDs—Deploy HDDs as data disks and deploy SSDs as read or write caches.
All SSDs—Deploy SSDs as data disks. Use this mode to provide high-performance storage. In this node, no read or write caches are used.
All HDDs—Deploy HDDs as data disks without read or write caches. Use this mode to provide regular storage services.
Cache Size: Set the cache size. This parameter is available only when you select the SSD Caches+HDDs deployment mode. The system divides SSDs into partitions based on the number of data disks and assigns a partition to each data disk as its cache. The default cache size is 50 GB. You can increase the cache size if the amount of service data is large.
Cache Protection Level: Select a cache protection level. This parameter is configurable when the service type is object storage or object storage-data pool and the deployment mode is SSD Caches+HDDs.
Standard—Cache and metadata are stored in cache disks in RAID0 mode.
Advanced—Cache and metadata are stored in cache disks in RAID1 mode. In the current software version, only some device models (such as R4900 G3) support the advanced level. For more information, see the compatibility matrixes.
You can view the following disk pool parameters:
Used: Physical disk capacity that is occupied by data in the disk pool.
Available Capacity: Available physical disk capacity of the disk pool.
Total: Total capacity of the disk pool, which equals the sum of the used capacity and available capacity.
Data Health: Health index for the data in the disk pool.
State: State of the disk pool.
Normal: The disk pool is operating correctly.
Abnormal: The disk pool does not contain data pools because it does not meet the redundancy policy requirements of any data pool, or the disk pool contains data pools but does not meet the redundancy policy requirements of the data pools. For example, if a disk pool uses hosts as fault domains and contains a data pool that needs three replicas, the disk pool must provide a minimum of three disks located on different hosts for the data pool. If the disk pool has only two available disks, its state is abnormal.