This command creates either a free-capacity array or an array with one logical drive when you enter a set of unassigned disk drives.
create array [arrayName] drives=(enclosureID1,slotID1 ... enclosureIDn,slotIDn) raidLevel=(0 | 1 | 3 | 5 | 6) [capacity=logicalDriveCapacity owner=(a | b) cacheReadPrefetch=(TRUE | FALSE) segmentSize=segmentSizeValue usageHint=(fileSystem | dataBase | multiMedia) enclosureLossProtect=(TRUE | FALSE) securityType=(none | capable | enabled)]
Parameter | Description |
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array | The alphanumeric identifier (including - and _) that you want to give the new array. Enclose the array identifier in square brackets ([ ]). |
drives | The disk drives that you want to assign to the array that you want to create. Specify the enclosure ID and slot ID for each disk drive that you assign to the array. Enclosure ID values are 0 to 99. Slot ID values are 1 to 32. Enclose the enclosure ID values and the slot ID values in parentheses. |
raidLevel | The RAID level of the array that contains the logical drive. Valid values are 0, 1, 3, 5, or 6. |
capacity | The size of the logical drive that you are adding to the storage subsystem. Size is defined in units of bytes, KB, MB, GB, or TB. These examples show the syntax:
capacity=500bytes capacity=2GB |
owner |
The setting for which controller owns the array. Valid controller identifiers are a or b, where a is the controller in slot A, and b is the controller in slot B. If you do not specify an owner, the controller firmware determines the owner. |
cacheReadPrefetch | The setting to turn on or turn off cache read prefetch. To turn off cache read prefetch, set this parameter to FALSE. To turn on cache read prefetch, set this parameter to TRUE. |
segmentSize | The amount of data (in KB) that the controller writes on a single disk drive in a logical drive before writing data on the next disk drive. Valid values are 8, 16, 32, 64, 128, 256, or 512. |
usageHint | The setting for both the cacheReadPrefetch parameter and the segmentSize parameter to be default values. The default values are based on the typical I/O usage pattern of the application that is using the logical drive. Valid values are fileSystem, dataBase, or multiMedia. |
enclosureLossProtect | The setting to enforce enclosure loss protection when you create the array. To enforce enclosure loss protection, set this parameter to TRUE. The default value is FALSE. |
securityType |
The setting to specify the security level when creating the arrays and all associated logical drives. These settings are valid:
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The drives parameter lets you choose the number of disk drives that you want to use in the array. If you choose this option, you do not need to specify the disk drives by enclosure ID and slot ID. The controllers choose the specific disk drives to use for the array.
If you do not specify a capacity by using the capacity parameter, all of the disk drive capacity that is available in the array is used. If you do not specify capacity units, bytes is used as the default value.
The cacheReadPrefetch command lets the controller copy additional data blocks into cache while the controller reads and copies data blocks that are requested by the host from the disk drives into cache. This action increases the chance that a future request for data can be fulfilled from cache. Cache read prefetch is important for multimedia applications that use sequential data transfers. The configuration settings for the storage subsystem that you use determine the number of additional data blocks that the controller reads into cache. Valid values for the cacheReadPrefetch parameter are TRUE or FALSE.
You do not need to enter a value for the cacheReadPrefetch parameter or the segmentSize parameter. If you do not enter a value, the controller firmware uses the usageHint parameter with fileSystem as the default value. Entering a value for the usageHint parameter and a value for the cacheReadPrefetch parameter or a value for the segmentSize parameter does not cause an error. The value that you enter for the cacheReadPrefetch parameter or the segmentSize parameter takes priority over the value for the usageHint parameter.
The size of a segment determines how many data blocks that the controller writes on a single disk drive in a logical drive before writing data on the next disk drive. Each data block stores 512 bytes of data. A data block is the smallest unit of storage. The size of a segment determines how many data blocks that it contains. For example, an 8-KB segment holds 16 data blocks. A 64-KB segment holds 128 data blocks.
When you enter a value for the segment size, the value is checked against the supported values that are provided by the controller at run time. If the value that you entered is not valid, the controller returns a list of valid values. Using a single disk drive for a single request leaves other disk drives available to simultaneously service other requests.
If the logical drive is in an environment where a single user is transferring large units of data (such as multimedia), performance is maximized when a single data transfer request is serviced with a single data stripe. A data stripe is the segment size that is multiplied by the number of disk drives in the array that are used for data transfers. In this case, multiple disk drives are used for the same request, but each disk drive is accessed only once.
For optimal performance in a multiuser database or file system storage environment, set your segment size to minimize the number of disk drives that are required to satisfy a data transfer request.
The securityType parameter is valid for disk drives that are capable of Full Disk Encryption (FDE). With FDE, the controller firmware can create a key and activate the disk drive security feature. The disk drive security feature encrypts data as the data is written to the disk drive and decrypts the data as the data is read from the disk drive. Without the key created by the controller, the data written to the disk drive is inaccessible.
Before you can set the securityType parameter to capable or enabled, you must create a storage subsystem security key. Use the create storageSubsystem securityKey command to create a storage subsystem security key. These commands are related to the securtiy key:
For enclosure loss protection to work, each disk drive in an array must be in a separate enclosure. If you set the enclosureLossProtect parameter to TRUE and have selected more than one disk drive from any one enclosure, the storage subsystem returns an error. If you set the enclosureLossProtect parameter to FALSE, the storage subsystem performs operations, but the array that you create might not have enclosure loss protection. Enclosure loss protection is not valid when you create logical drives on existing arrays.
7.10
7.50 adds the securityType parameter.