Air Cleaner User Manual

the disk or disks appear to be missing. You can the use the Edit volume group
and logical volume attributes option to re-select the drives for each volume group.
IBM 7135 RAIDiant Array
The IBM 7135 is not a supported boot device by AIX. During the SysBack system
installation process, AIX recognizes the disks as “Other SCSI Disk”. AIX cannot,
however, create a volume group on the disks at this time. The 7135 should be
powered off or disconnected when using SysBack to install the system.
When the installation is complete and before rebooting the system in normal mode,
power on the 7135. Each of the 7135 disks is then recognized as a “7135 Disk Array
Device”, assuming the 7135 device support was installed on the system. You can
then recreate and restore volume groups on the 7135 disks using the SysBack
system backup.
When AIX is installed, it “walks the bus,” configuring all disks in the order in
which they appear. Powering off the 7135 during installation of the rootvg ensures
that the internal disk drives, onto which the rootvg volume group is installed, are
named with the first hdisk names (e.g, hdisk0).
IBM 7137 and Other RAID Devices
RAID storage units have a number of unique features that vary depending upon
the actual RAID box and have an impact on the use of SysBack. RAID boxes
provide fault tolerance in case of a disk failure (except for RAID-0, which is simply
a form of disk striping). Most implementations of RAID use RAID-5 or RAID-1,
which provide fault tolerance for a disk failure.
Before a RAID box can be used, it must be configured. This often includes
choosing the RAID level, number of LUNs (known as “hdisks” to AIX), size, and
other characteristics. Creating and configuring the LUNs is done in various ways:
through software on the RS/6000 such as for the IBM 7135, through a keypad on
the RAID box such as for the IBM 7137, or through other means such as a terminal
attached to the RAID box, switch settings, and so on. Only after the LUNS are
configured in the system do the “hdisks” become available for use in AIX volume
groups.
Some RAID devices, including the 7137, are recognized by AIX without the need to
configure any software on the system; however, the disk descriptions show as
“Other SCSI disks”. In most cases, as with the 7137, the disks can be used by AIX
with no further software configuration. Because no special software configuration
is required, they can be recognized by the SysBack installation process and can be
included in any volume group, including the rootvg volume group.
If the RAID device requires special device drivers or software customization before
they can be used, they are either unrecognized or unusable during the SysBack
installation process. If this is the case, power off the unit during the installation
process to ensure that the remaining system disks receive the first available
“hdisk” names. After the rootvg volume group is installed on other supported
disks, you can power on the RAID unit before rebooting the system in normal
mode. At that time, assuming the RAID software support is installed, the RAID
disks can then be configured into the system. Additional volume groups can be
recreated and restored from the SysBack system backup onto the RAID disks.
E-4 IBM Tivoli Storage Manager for System Backup and Recovery: Installation and User’s Guide