IBM RS/6000 - Manual (Page 178)

8.3.3 Maintenance Mode
Diagnostics can run from Single-User mode (Maintenance mode - although this is
different from booting into Maintenance mode from a CD-ROM or a tape). You can
shut your system down into a Single-User mode which will allow testing many of
your system resources which would normally be in use while AIX is running. All the
system resources, except the SCSI adapters and disks used for paging, memory
and processors, can be tested. Error Log Analysis is available in this mode. Other
users will not be allowed to log into the system while the system is in Single-User
mode.
Logged on as root, you can enter diagnostics in Single-User (Maintenance) mode
by performing the following:
1. Stop all applications and log all users off the system.
2. Enter the shutdown -m command.
3. When a message indicates the system is in Maintenance mode, enter the diag
command.
4. When the Diagnostic Operating Instructions area is displayed, follow the
instructions to check the desired resources.
After you have completed testing the system, you can shut down and reboot the
system.
8.4 Using NIM to Run Online Diagnostics over the Network
Hardware diagnostics can be performed on all NIM Clients by using a diagnostic
boot image from a NIM Master rather than booting from a diagnostic CD-ROM or
from a local Online Diagnostics package. This is useful on stand-alone Clients,
which don't have the
bos.diag package installed on the local disk. Before the Client
can be booted in Diagnostic mode, the following conditions must be met:
1. The Client must have a spot NIM resource object allocated to it (see 9.1.2,
“NIM Objects” on page 158).
2. The diag NIM operation must be performed on the specific Client. This
operation prepares the resources a Client requires for a network diagnostics
boot.
8.4.1.1 Creating a NIM Environment for Diagnostics
The procedure to create a NIM diagnostic environment is the same as described in
Chapter 9, “Network Installation Management (NIM) Support” on page 157 First,
you have to define the lpp_source resource object (see 9.2.6.1, “Defining the
lpp_source Resource Object” on page 169); then, the spot resource must be
defined (see 9.2.6.2, “Defining the Shared Product Object Tree (SPOT) Resource
Object” on page 170).
Unlike using NIM to install a Client machine over the network, where two NIM
resources,
lpp_source and spot, need to be allocated to the Client (see 9.2.7,
“Allocating Resources for the Stand-Alone Installation” on page 172), in the case of
diagnostics, only the
spot resource has to be allocated.
154 Introduction to PCI-Based RS/6000 Servers