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Creating thin volumes on a disk pool

If you want to add a new thin volume to an existing disk pool, use this command:

create volume diskPool="diskPoolName" 
userLabel="volumeName" capacity=volumeVirtualCapacity 
thinProvisioned=TRUE 
[owner=(a|b) | 
mapping=(none|default) | 
dataAssurance=(none|enabled) | 
(existingRepositoryLabel=existingRepositoryName | 
newRepositoryCapacity=newRepositoryCapacityValue [KB | MB | GB | TB | Bytes]) | 
repositoryMaxCapacity=repositoryMaxCapacityValue[KB|MB|GB|TB|Bytes] | 
repositoryExpansionPolicy=(automatic|manual) | 
warningThresholdPercent=warningThresholdPercentValue | 
cacheReadPrefetch=(TRUE | FALSE)]
Note: The thinProvisioned parameter is required to create a thin volume on a disk pool.

The diskPool parameter is the name of the disk pool in which you want to create a new thin volume. If you do not know the disk pool names on the storage array, you can use the show allVolumes summary command to get a list of the volumes and the disk pools to which the volumes belong.

The userLabel parameter is the name that you want to give to the disk pool. The disk pool name can be any combination of alphanumeric characters, hyphens, pound (#), and underscores. The maximum length of the disk pool name is 30 characters. You must enclose the disk pool name with double quotation marks (“ ”).

The capacity parameter defines the virtual capacity of the thin volume. The capacity is the value that is reported to the host. As users add information to the thin volume the physical size of the volume increases. When you define the capacity of the thin volume you must define a capacity of at least 32 GB. The maximum capacity that you can define is 64 TB for standard volumes and 256 TB for thin volumes.

Set the thinProvisioned parameter to TRUE to create a thin-provisioned volume.

The Data Assurance (DA) feature increases data integrity across the entire storage system. DA enables the storage array to check for errors that might occur when data is moved between the hosts and the drives. When this feature is enabled, the storage array appends error-checking codes (also known as cyclic redundancy checks or CRCs) to each block of data in the volume. After a data block is moved, the storage array uses these CRC codes to determine if any errors occurred during transmission. Potentially corrupted data is neither written to disk nor returned to the host.

If you want to use the DA feature, start with a volume group or disk pool that includes only drives that support DA. Then, create DA-capable volumes. Finally, map these DA-capable volumes to the host using an I/O interface that is capable of DA. I/O interfaces that are capable of DA include Fibre Channel, SAS, and iSER InfiniBand (iSCSI Extensions for RDMA/IB). DA is not supported by iSCSI over TCP/IP, or by the SRP InfiniBand interface.

Note: When all the required hardware and the I/O interface is DA-capable, you can set the dataAssurance parameter to enabled and then use DA with certain operations. For example, you can create a volume group that includes DA-capable drives, and then create a volume within that volume group that is DA-enabled. Other operations that use a DA-enabled volume have options to support the DA feature.

The mapping parameter defines whether you want the storage management software to map the volume to a host, or if you want to map the volume to a host later. To allow the storage management software to map the volume to a host use the default parameter. To map the volume to a host later, use the none parameter. To map a volume to a host, use the set volume mapping command.

The repository capacity is the actual physical capacity of the thin volume. The value that you use for the repository capacity is the starting size of the physical component of a thin volume. The minimum capacity that you can define for the repository must be at least 4 GB. The maximum capacity that you can define is 256 TB. You can use a small starting value for the repository. As data increases in the repository, additional volumes are added to the repository to increase the capacity. You can either use an existing repository or create a new repository with this command. The repository capacity is governed by these parameters:

The warningThresholdPercent parameter defines when you receive a warning that the repository volume is nearing maximum capacity. The value for this parameter is a percentage of the maximum capacity of the repository volume.

To turn on cache read prefetch, set the cacheReadPrefect parameter to TRUE .