Preparing disks for use in SAS disk arrays
Use this information to prepare disks for use in an array.
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, do the following:
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.
