How to fix BLV of AIX

If a boot logical volume is corrupted (for example, bad blocks on a disk might cause a corrupted BLV), a machine will not boot.

To fix this situation, you must boot your machine in maintenance mode, from a CD or tape. If NIM has been set up for a machine, you can also boot the machine from a NIM master in maintenance mode. By the way, that's what you would do on an SP node if an SP node does not boot.

The boot lists are set using the bootlist command or the System Management Services (SMS) program. Some machines support a normal and service boot list. If your model supports this, you will use a function key during bootup to select the appropriate list. Normally, pressing F5 when you hear the first tones during bootup, will force the machine to check for a bootable CD. More on this later.

After booting from CD, tape or NIM an Installation and Maintenance Menu is shown and you can startup the maintenance mode. We will cover this later in this unit. After accessing the rootvg, you can repair the boot logical volume with the bosboot command. You need to specify the corresponding disk device, for example hdisk0:

# bosboot -ad /dev/hdisk0

It is important that you do a proper shutdown. All changes need to be written from memory to disk.

The bosboot command requires that the boot logical volume hd5 exists. If you ever need to re-create the BLV from scratch - maybe it had been deleted by mistake - the following steps should be followed:

1. Boot your machine in maintenance mode (from CD or tape).

2. Create a new hd5 logical volume: one physical partition in size, must be in rootvg. Specify boot as logical volume type.

3. Run the bosboot command as described.

4. Reboot the server run command

# shutdown -Fr

The following is an example of re-creating boot logical volume (BLV)

1. Boot your machine in maintenance mode (from CD, tape, or NIM).

2. Create a new hd5 logical volume: one physical partition in size, must be in rootvg. Specify boot as logical volume type. if needed, remove hd5 using # rmlv -f hd5

# mklv -y hd5 -t boot -a e rootvg 1

3. Run the bosboot command as described below.

# bosboot -ad /dev/hdisk0

4. Shutdown -Fr.