IBM SA23-1325-01 manual Using Disk Arrays, Using AIX, Using Linux

Chapter 6. Using Disk Arrays

This chapter provides information about using the RAID-related features of this adapter. The following tasks are beyond the scope of this installation guide and are usually performed by system administrators.

vTo use the RAID-related features of the hardware, disk arrays must be created first.

vAIX and Linux use and manage the disk array in the same way as it would a single non-RAID disk.

vFor optimum performance, distribute the hard disk drives equally across the available channels.

Using AIX

For an overview of RAID and detailed procedures, refer to the PCI-X SCSI RAID Controller Reference Guide for AIX, order number SA23-1323.

vDisk drives previously installed in this system probably have 512 bytes/sector.

vTo use the drives in disk arrays with this adapter, the disk drives must be prepared by formatting them to 522 bytes/sector.

vDisk drives in 512 bytes/sector format may continue to be used as standalone disks (that is, not part of a disk array) on this RAID adapter. Additionally, drives formatted to 522 bytes/sector may be reformatted to 512 bytes/sector at a later time if desired for compatibility with previous adapters.

vFormatting of drives to 522 bytes/sector and the creation of disk arrays may require that data previously written on the drives be saved and restored after the the disk arrays are created.

vIf a disk array is to be used as the boot device, it may be required to prepare the disks by booting from the Diagnostic CD and creating the disk array before installing AIX. You might want to perform this procedure when the original boot drive is to be used as part of a disk array.

Using Linux

For an overview of RAID and detailed procedures, refer to the PCI-X SCSI RAID Controller Reference Guide for Linux, order number SA23-1327.

vDisk drives previously installed in this system are probably JBOD drives. JBOD drives are formatted to 512 bytes/sector.

vTo use the drives in disk arrays with this adapter, the disk drives must be prepared by formatting them to 522 bytes/sector.

vDisk drives in 512 bytes/sector format may continue to be used as standalone disks (that is, not part of a disk array) on this RAID adapter. Additionally, drives formatted to 522 bytes/sector for advanced function may be reformatted to 512 bytes/sector at a later time if desired for compatibility with previous adapters.

vFormatting of drives to 522 bytes/sector for advanced function and the creation of disk arrays may require that data previously written on the drives be saved and restored after the disk arrays are created.

vIf a disk array is to be used as the boot device, it may be required to prepare the disks by booting into rescue mode from the Linux CD first. If your Linux distribution does not provide this feature, the Diagnostic CD may be used. You might want to perform this procedure when the original boot drive is to be used as part of a disk array.

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