Preparing disks for use in SAS disk arrays

Use this information to prepare disks for use in an array.

About this task

Before a disk can be used in a disk array, it must be a Array Candidate pdisk. Array Candidates are physical disks that are formatted to a block size that is compatible with SAS RAID. The RAID block size is larger than a JBOD block size due to the SCSI T10 standardized data integrity fields along with logically bad block checking stored on each block with the data. The SAS RAID adapters support disk blocks based on 512 Bytes of data or 4K Bytes of data. The RAID block size for the 512 disks is 528 Bytes per sector and the RAID block size for the 4K disks is 4224 Bytes per sector.

To create an Array Candidate pdisk and format it to RAID block size, complete the following steps:

Procedure

  1. Start the IBM® SAS Disk Array Manager by following the steps in Using the Disk Array Manager.
  2. Select Create an Array Candidate pdisk and Format to RAID block size.
  3. Select the appropriate controller.
  4. Select the disks that you want to prepare for use in the SAS disk arrays.
    Attention: Continuing with this option will format the disks. All data on the disks will be lost.

    A message will display asking if you want to continue.

  5. To proceed with the format, select OK or press Enter to continue.
    To return to the previous menu without formatting the disks, select Cancel.

Results

After the formatting is complete, the disks will be Array Candidate pdisks and will be ready for use in disk arrays. This operation will also zero all the data on the disks. The controller keeps track of the disks that have their data zeroed. These Zeroed Array Candidate pdisks can be used to create a disk array that will be immediately protected against disk failures, and they are the only disks that can be added to an existing disk array. An Array Candidate pdisk will lose its Zeroed state after it has been used in an array or is unconfigured. It will also lose its Zeroed state after the system has been rebooted or the controller has been unconfigured. To return an Array Candidate pdisk to the Zeroed state, follow the steps previously described in this section for preparing disks for use in disk arrays. For more information, see Disk arrays.