Creating an IBM SAS RAID disk array

A disk array is created using a set of disks that are formatted for advanced function.

About this task

For disk arrays with data redundancy (RAID 5, 6, 10, 5T2, 6T2, and 10T2), if all of the disks are in the Zeroed state, the array becomes immediately protected against failures. However, if one or more of the disks are not Zeroed, the newly created array will initially be in the Rebuilding state. It will be unprotected against disk failures until parity data on all of the disks has been recalculated. Ensure that all disks are placed in a Zeroed state by selecting Create an Array Candidate pdisk and format to RAID block size before creating a disk array to fully initialize the disks and provide the shortest time to create the disk array.

A RAID array must be entirely composed of devices from the same device class. Multiple disk arrays, consisting of different device classes, may coexist on the same controller. The following are the supported device classes:

528 HDDs (10K or 15K)
4K HDDs (10K or 15K)
4K Nearline HDDs
528 SSDs
4K SSDs
528 Read Intensive (Mainstream) SSDs
4K Read Intensive (Mainstream) SSDs

Complete the following steps to create an IBM® SAS RAID disk array:

Procedure

Run the iprconfig utility by typing iprconfig.
Select Work with disk arrays.
Select Create a disk array.
Select the controller under which you would like to create a disk array, and then press Enter.

Select the disk units to be included in the disk array, and then press Enter.

If the disks do not have a status of Zeroed, first format them using the instructions provided at Formatting to advanced function. Formatting the disks reduces the overall RAID creation time and ensures the RAID array is fully optimized following RAID creation. The information that you see will be similar to the following screen:

+--------------------------------------------------------------------------------+
|                    Select Protection Level and Stripe Size                     |
|                                                                                |
| Default array configurations are shown.  To change                             |
| setting hit "c" for options menu.  Highlight desired                           |
| option then hit Enter                                                          |
|                                                                                |
| c=Change Setting                                                               |
|                                                                                |
|Protection Level . . . . . . . . . . . . :  RAID 5                              |
|Stripe Size  . . . . . . . . . . . . . . :  256 k                               |
|Queue Depth (default =  12). . . . . . . :  12                                  |
|                                                                                |
|Press Enter to Continue                                                         |
|                                                                                |
|e=Exit   q=Cancel                                                               |
+--------------------------------------------------------------------------------+

Select the protection level that you want for the array.
For more information about selecting an appropriate RAID level, see Supported RAID levels.
Select the stripe size that you want, in kilobytes, for the array.
For more information about selecting an appropriate stripe size, see Stripe-unit size.
Press Enter to continue.
Attention: All data on the selected drives will be lost when the disk array is created. If you are sure you want to create the disk array, press Enter. If you do not want to create the disk array, type q to cancel.

If you choose to create the disk array, a status screen is displayed until the operation is completed. If you want to create additional disk arrays, you can exit the status screen by typing e.

Results

When a disk array has been built, it is available to the Linux® operating system like any SCSI disk. To find the resource name that has been assigned to the disk array, see the Display Disk Array Status screen.

Note: Resource names (such as /dev/sdb) might change as a result of creating a new disk array. This could affect kernel command line entries and fstab entries. You might want to reboot the server now.