Mirroring the rootvg Volume Group for AIX 4.1/4.2
Article Number: 16 | Rating: Unrated | Last Updated: Mon, May 21, 2018 9:32 PM
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.
- Replace a broken disk
1. To replace a bad disk drive in a mirrored volume group, enter unmirrorvg workvg hdisk7 reducevg workvg hdisk7 rmdev -l hdisk7 -d replace the disk drive, let the drive be renamed hdisk7 extendvg workvg hdisk7 mirrorvg workvg Note: By default in this example, mirrorvg will try to create 2 copies for logical volumes in workvg. It will try to create the new mirrors onto the replaced disk drive. However, if the original system had been triply mirrored, there may be no new mirrors created onto hdisk7, as other copies may already exist for the logical volumes. 2. To sync the newly created mirrors in the background, enter: mirrorvg -S -c 3 workvg 3. To create an exact mapped volume group, enter: mirrorvg -m datavg hdisk2 hdisk3
Last Update November 11, 1998 Eva Hocks