Mirroring the rootvg Volume Group for AIX 4.1/4.2
The disks that constitute the boot drives for AIX, must be disks that
are supported to boot on RS/6000 platforms. A machine and disk
configuration may be queried to determine if that combination of
machine and disk supports booting from disk:
bootinfo -B hdiskX
If the command returns a "1" then it will be bootable by AIX. Any
other value indicates that this disk is not a candidate for rootvg
mirroring.
Procedure:
The following steps assume the user has rootvg contained on hdisk0 and is
attempting to mirror the rootvg to a new disk hdisk1.
1. Extend rootvg to hdisk1:
extendvg rootvg hdisk1
If the user encounters the error message:
0516-050 Not enough descriptor space left in this volume group.
Either try adding a smaller PV or use another volume group.
Then the user may not add hdisk1 to rootvg for mirroring. The user may
attempt to mirror rootvg's logical volumes to another disk that
already exists in rootvg and meets the criteria and restrictions
listed in the "restrictions" section above. The user may also attempt
to add a smaller disk to the rootvg. If neither option is possible,
then mirroring rootvg cannot be performed on this system.
2. Disable QUORUM, by running the following:
chvg -Qn rootvg
3. Mirror the logical volumes that make up the AIX operating system:
mklvcopy hd1 2 hdisk1 # /home file system
mklvcopy hd2 2 hdisk1 # /usr file system
mklvcopy hd3 2 hdisk1 # /tmp file system
mklvcopy hd4 2 hdisk1 # / (root) file system
mklvcopy hd5 2 hdisk1 # blv, boot logical volume
mklvcopy hd6 2 hdisk1 # paging space
(if the user has other paging devices, rootvg and non-rootvg, they
must also mirror those logical volumes in addition to hd6)
mklvcopy hd8 2 hdisk1 # file system log
mklvcopy hd9var 2 hdisk1 # /var file system
If hd5 consists of more than one logical partition, then after
mirroring hd5 the user must verify that the mirrored copy of hd5
resides on contiguous physical partitions. This can be verified with
the command:
lslv -m hd5
If the mirrored hd5 partitions are not contiguous, then the user must
delete the mirror copy of hd5 (on hdisk1) and rerun the mklvcopy for
hd5 using the "-m" option. The user should consult documentation on
the usage of the "-m" option for mklvcopy.
4. Synchronize the newly created mirrors:
syncvg -v rootvg
5. Bosboot to initialize all boot records and devices:
bosboot -a
6. Initialize the boot list:
bootlist -m normal hdisk0 hdisk1
Warning: Even though this command identifies the list of possible boot
disks it does not guarantee that the system will boot from the
alternate disk in all cases involving failures of the first disk. In
such situations, it may be necessary for the user to boot from the
installation/maintenance media, select maintenance, reissue the
bootlist command leaving out the failing disk, and then reboot. On
some models, firmware provides a utility for selecting the boot device
at boot time. This may also be used to force the system to boot from
the alternate disk.
7. Shutdown and reboot the system:
shutdown -Fr
This is so that the "Quorum OFF" function takes effect.
Last Update November 11, 1998 Eva Hocks