Introduction to the AIX server startup process

1) Start

When you enable the system by enabling the power switch or using the reboot and shutdown commands, the following events may occur before the system is available:

<! -- [If! SupportLists] --> 1, <! -- [Endif] --> ROS kernel initialization stage

The ROS kernel resides in the firmware.

The initialization phase includes the following steps:

A.) Check the firmware to check whether the system board has any problems. Control is passed to ROS, which executes POST after-boot self-check ).

B) Check the list of available boot devices in the user boot list ). You can use the bootlist command to change the bootstrap list to suit your needs. If the user boot list in the non-volatile random access memory NVRAM) is invalid or no valid boot device is found, check the default boot list. In either case, the first valid boot device found in the boot list is used for system startup. If a valid user guide list exists in NVRAM, check the devices in the list in sequence. If the user boot list does not exist, check all the adapters and devices on the bus. In either case, the device is checked continuously until a valid boot device is found for the system boot.

Note: For normal boot, the system retains the default boot list in ROS and the user boot list stored in NVRAM. Separate default and user guide lists are also retained for guidance from critical service locations.

C) Check the first record or program sector number PSN when a valid boot device is found ). If it is a valid Boot Record, it is read into the memory and added to the IPL control block in the memory. The starting position of the boot image on the boot device, the length of the boot image, and instructions on where to mount the Boot Image in memory are included in the key Boot Record Data.

D) read the boot image from the boot device to the memory in sequence starting from the specified position in NVRAM. The disk boot image includes kernel, RAM file system, and basic custom device information.

E.) control is passed to the kernel to start system initialization.

F.) run init in the kernel. This command runs Stage 1 of the rc. boot script.

When the kernel initialization phase is complete, the basic device configuration starts.

2) start Phase 1

The init process starts the rc. boot script. In stage 1 of the rc. boot script, configure the basic device.

Stage 1 of the rc. boot script includes the following steps:

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

B) boot script to start the Configuration Manager, which accesses Phase 1 ODM configuration rules to configure the basic device.

C) Configuration Manager starts sys, bus, disk, SCSI, and logical volume manager LVM) and rootvg volume group configuration method.

D.) This configuration method loads the device driver, creates a special file, and updates the customized data in the ODM database.

3) Phase 2

Boot system rc. boot Phase 2 and 3)

Follow these steps to complete the system boot phase.

The init process starts Stage 2 of running the rc. boot script. Rc. boot stage 2 includes the following steps:

A.) Call the ipl_varyon program to bring the rootvg volume group online.

B) install the hard disk file system on their normal installation points.

C.) run the swapon program to start page scheduling.

D. Copy the customized data from the ODM database in the RAM File System to the ODM database in the hard disk file system.

E.) Exit the rc. boot script.

After rc. boot stage 2, the boot process is switched from the RAM File System RAMFS to the hard disk root file system.

Mount the rootvg file system and change it to the availble state. Now mount the/var and/usr file systems in rootvg respectively.

The init process then runs the process defined by the records in the/etc/inittab file. In the/etc/inittab file, run stage 3 of the rc. boot script, which includes the following steps:

A.) install the/tmp hard disk file system.

B.) Rootvg starts to call the syncvg command synchronously in the background. The LED code displays 553

C) Start ipvmgr Stage 2 in normal mode to configure all the remaining devices. When service mode is started, zoomgr selects Phase 3 for configuration. zoomgr reads the config_rules file from the ODM library and reads the file from rc. in Stages 2 and 3 of boot, call the corresponding method to configure other devices.

D) Use the savebase command to save the customized data to the boot logical volume.

D.) Exit the rc. boot script.

At the end of this process, the system has been started and can be used.

Boot LED code:

LED 201-Damaged boot image

LED 223-229-Invalid boot list

LED 551,555, and 557-converted upted file system, synchronized upted JFS log, and so on

LED 552,554, and 556-Super block upload upted and custom upted customized ODM

Database

LED 553-upted/etc/inittab file

LED c31: Console not yet configured. Provides instructions to select console.

LED c32: Console is an LFT terminal.

Bootlist common options

Bootlist-m normal-o displays the currently set bootlist

Bootlist-m normal hdisk0 hdisk1 modify bootlist

System running level

Table 4-4 Run levels available on AIX 5L

Run level Description

0-1 Reserved for the future use of the operating system.

2 Contains all of the terminal process and daemons that are run in

Multiuser environment. This is the default run level.

3-9 Can be defined according to the user's preferences

A, B, c, h These are not true run levels; they differ from run levels in that the init

Command cannot request the entire system to enter these run levels.

See 4.3, "The/etc/inittab file" on page 98 for more information.

S, s, M, m Maintenance mode. When the system enters maintenance mode from

Another run level, only the system console is used as the terminal.

Run level Description

Displays the running level of the current system.

Cat/etc/. init. state

List the changes of the system running level

/Usr/lib/acct/fwtmp </var/adm/wtmp | grep run-level

Change the system running level:

Telinit N

/Sbin/rc. boot is called by init and different parameters are called at different stages of startup. :

Booting from disk boot phase 1)

Varying on a root volume group boot phase 2)

Enabling file systems boot phase 2)

Calling the BOS installation programs or diagnostics

/Etc/rc is used to start the system after rc. boot

Vary on all volume groups marked as auto-varyon.

Activate all paging spaces listed on/etc/swapspaces using the swapon-

Command ).

Configure all dump devices using the sysdumpdev-q command ).

Perform file system checks using the fsck-fp command ).

Perform mounting of file systems marked as mount = true on

/Etc/filesystems file using the mount all command ).

/Etc/rc.net start Network

/Etc/rc. tcpip start the tcpip Service

Inetd started by default)

Gated

Routed

Named

Timed

Rwhod

There are also daemons specific to the base operating system or to other

Applications that can be started through the rc. tcpip file. These daemons are:

Lpd

Portmap

Sendmail

Syslogd

Oracle video tutorial follow: http://u.youku.com/user_video/id_UMzAzMjkxMjE2.html