Boot Process for AIX server

(1) Start

When you start the system by turning on the power switch or by using the reboot and shutdown commands, the following phases of events occur before the system is available:

<!--[if!supportlists]-->1, <!--[Endif]-->ros kernel initialization phase

The ROS kernel resides in the firmware

Its initialization phase consists of the following steps:

A.) The firmware performs a check to see if there is any problem with the system board. The control is passed to ROS, which performs the power-on self-test (POST).

B. ROS initialization program loading (IPL) Check the user bootstrap list (list of available boot devices). You can use the bootlist command to change this boot list to suit your needs. If the user boot list in the Non-volatile Random access memory (NVRAM) is invalid or a valid boot device cannot be found, the default boot list is checked. In either case, the first valid boot device found in the boot list will be used for system startup. If there is a valid user bootstrap list in the NVRAM, check the devices in the list in turn. If no user bootstrap list exists, all adapters and devices on the bus are checked. In either case, the device is checked in a continuous loop until a valid boot device is found for the system startup.

Note: For normal booting, the system retains the default boot list in ROS and the user bootstrap list stored in NVRAM. A separate default and user bootstrap list is also maintained to boot from the service critical location.

C. When a valid boot device is found, check the first record or program sector number (PSN). If it is a valid boot record, it is read into memory and added to the IPL control block in memory. Included in the key boot record data is the starting position of the boot image on the boot device, the length of the boot image, and the indication of where to mount the boot image in memory.

D.) reads the boot image from the boot device sequence to memory starting at the location specified in the NVRAM. Disk boot images include kernel, RAM file system, and basic custom device information.

E.) control is passed to the kernel, initiating system initialization.

F.) The kernel runs init, and this command will run Phase 1 of the Rc.boot script.

When the kernel initialization phase completes, the basic device configuration begins.

(2) The start-up phase of a

The init process will start the Rc.boot script. Phase 1 of the Rc.boot script performs the basic device configuration.

Phase 1 of the Rc.boot script includes the following steps:

A.) The boot script invokes the Restbase program to build a custom Object Data Manager (ODM) database from compressed custom data in the RAM file system.

B.) Boot script launch Configuration Manager, which accesses the Phase 1 ODM configuration rules to configure the basic devices.

C.) Configuration Manager startup sys, bus, disk, SCSI, and Logical Volume Manager (LVM), and ROOTVG volume group configuration methods.

D.) This configuration method loads device drivers, creates special files, and updates custom data in the ODM database.

(3) Start phase Two

Boot System (Rc.boot Stage 2 and 3)

Use the following steps to complete the system boot phase.

The init process starts Phase 2 of running the Rc.boot script. The Rc.boot Phase 2 consists of the following steps:

A.) calls the Ipl_varyon program to bring the ROOTVG volume group online.

B. Install the hard disk file system on their normal installation point.

C.) Run the Swapon program to start page scheduling.

D.) Copy custom data from the ODM database in the RAM file system to the ODM database in the hard disk file system.

E.) Exit Rc.boot script.

After Phase 2 of rc.boot, the boot process switches from the RAM file system (RAMFS) to the hard disk root file system.

Mount the ROOTVG file system so that it becomes availble state. The/var and/usr file systems in ROOTVG are now mounted separately.

The init process then runs the process defined by the records in the/etc/inittab file. An instruction in the/etc/inittab file runs Phase 3 of the Rc.boot script, which includes the following steps:

A.) Install the/TMP hard disk File system.

B.) ROOTVG began synchronizing the call SYNCVG command in the background, at which point the LED code would show 553

C.) Start Normal mode cfgmgr phase and configure all remaining devices. Starting service mode mode Cfgmgr will select Phase 3 to configure, Cfgmgr will read config_rules files from the ODM library and will call the appropriate method to configure other devices from Rc.boot stages 2 and 3.

D.) Use the Savebase command to save custom data to a boot logical volume.

D.) Exit Rc.boot script.