Clone or mirror your AIX OS larger disk to smaller disk ?

hello folks,

I have a 300GB ROOTVG volume groups with one filesystem /backup having 200GB allocated space

Now, I cannot alt disk clone or mirrorvg this hdisk with another smaller disk. The disk size has to be 300GB; I tried alt disk clone and mirrorvg , it doesn't work. you cannot copy LVs as operating system has some lv which cannot be copied other than mirrorvg..

is there a way to make another smaller hdisk = 10GB have a copy of only the AIX operating system from the already existing hdisk which is 300GB ?

thanks

You could do this.

  1. Backup and delete the /backup filesystem
  2. Add another smaller disk to the rootvg (make sure it is big enough to hold all the remaining LVs)
  3. Move the LVs to the new disk with "migratepv -l ..."
  4. Remove the 300GB disk from rootvg
  5. Create a new VG (named something like backupvg) and create a /backup filesystem in it and mount it
  6. Restore the /backup contents into the new /backup filesystem

Hi,
you may not be able to do a mirrorvg but I cannot see what would prevent you from mirroring the lv's (except the backup lv) after adding the smaller disk to rootvg - and then simply do a new bosboot on both disks and create a new bootlist ?

You could as well take (for safety purposes) take a mksysb from rootvg and exclude the backup filesystem.

Regards
zxmaus

It took me too long to find the term I was looking for - kept thinking multi-boot (which is for something else!).

I think what you might be looking for is multibos . The trouble is going to continue to be that /backup is in rootvg and I do not know if it will be available on a second boot (with the multibos)

In short, what multibos does is copy the current rootvg (key) logical volumes - giving them different names (much like alt_disk_install does, but now within the current volume group).

Assumming /backup (since it is not a default rootvg logical volume) will be available after a reboot to the "other" rootvg you could attempt, assuming the sum of the current PP sizes are less than 10G:

1. Backup /backup to other medium
2. Add 10G disk to rootvg
3. Use multibos procedure to copy current rootvg key logical partitions to 10G disk.
4. reboot to 10G disk
5. remove other copy of rootvg and /backup
6. remove disk from rootvg (reducevg)
7. Create new volume group for backups
8. Restore /backup to new volume group.

For more on multibos look at two articles on IBM Systems Magazine: AIX-Updates-With-Multibos/ and Working with Multibos

However, I would also consider using the information above from ka00na and zxmaus to "almost" use mirrorvg - by just adding the key AIX partitions
to the 10G disk, backup and remove /backup; then remove the copies on original disk; and restore /backup - roughly this:

# extendvg rootvg hdisk1
# for i in hd1 hd2 hd3 hd4 hd5 hd6 hd7 hd8 hd9var hd10opt hd11admin lg_dumplv hd12audit
do
mklvcopy $i 2 hdisk1
done
# bosboot -ad hdisk1
# echo do backup of whatever needs backing up
# for i in hd1 hd2 hd3 hd4 hd5 hd6 hd7 hd8 hd9var hd10opt hd11admin lg_dumplv hd12audit
do
rmlvcopy $i 1 hdisk0
done
# reducevg -d -f rootvg hdisk0
# chpv -c hdisk0
# mklv -y vgBackup hdisk0 # consider adding -t and/or -s arguments to manage PP size)
# echo "restore saved data from above"

Hope this helps!

Okay,

I have a 10GB hdisk with AIX 5.3 with 0 free PPs, and I assigned a 15GB hdisk
made a successful alt_disk_clone on the new empty disk , however the new cloned disk should have free PPs but as it is cloned there is no free PPs.

Is there any way to allocate free PPs for the volume group of the cloned disk ?

Thanks

root@test1:/>lsvg rootvg

VOLUME GROUP:       rootvg                   VG IDENTIFIER:  00c7780e00004c000000013b4d2a9ce3
VG STATE:           active                   PP SIZE:        512 megabyte(s)
VG PERMISSION:      read/write               TOTAL PPs:      19 (9728 megabytes)
MAX LVs:            256                      FREE PPs:       0 (0 megabytes)
LVs:                10                       USED PPs:       19 (9728 megabytes)
OPEN LVs:           9                        QUORUM:         1
TOTAL PVs:          1                        VG DESCRIPTORS: 2
STALE PVs:          0                        STALE PPs:      0
ACTIVE PVs:         1                        AUTO ON:        yes
MAX PPs per VG:     32512                                    0
MAX PPs per PV:     1016                     MAX PVs:        32
LTG size (Dynamic): 256 kilobyte(s)          AUTO SYNC:      no
HOT SPARE:          no                       BB POLICY:      relocatable


will running this command help

 chvg -t 2 rootvg
0516-1193 chvg: WARNING, once this operation is completed, volume group rootvg
        cannot be imported into AIX 430 or lower versions. Continue (y/n) ?
y
0516-1164 chvg: Volume group rootvg changed.  With given characteristics rootvg
        can include upto 16 physical volumes with 2032 physical partitions each.

VOLUME GROUP in AIX - web-manual

I made a clone from a 10GB rootvg on 15GB rootvg , should I get the 5GB as free space -- which I am not getting it !

Because you cloned a 10gb vg you got a 10gb vg.

Check out the chvg switch -g:

-g Will examine all the disks in the volume group to see if they have grown in size. If any disks have grown in size attempt to add additional PPs to PV. If necessary will determine proper 1016 multiplier and conversion to big vg.

pSeries and AIX Information Center

HTH

chvg -g will not work rootvg

root@test1:/>chvg -g rootvg
0516-1380 chvg: Re-sizing of the disks is not supported for the rootvg.
0516-732 chvg: Unable to change volume group rootvg.

any other ideas ?

Yes: start over. Obviously what you want is not a clone. A clone is an identical copy - up to the size information. Dukessd has already said it: clone a 10GB-disk and you get another 10GB-disk. What you want is a different disk with the same content as the original. For this purpose everything "clone" is the wrong tool.

First, use "extendvg" to make the new disk part of the rootvg. Then "mirrorvg" to create copies of the LVs on the new disk. Wait, because this will take some time (depending on the load the system is under and the traffic on the rootvg some minutes to half an hour approximately).

Perform a "bosboot" to create a boot block on the new disk. Then shut down the system. Disconnect the newly created disk and boot again. Correct the errors because of the now missing disk. (Don't forget to correct the bootlist too.)

Start a new system with the cloned disk. You will have to correct the same errors because of the missing mirror disk on the new system. Note that you have an absolutely identical copy of the system - connect both to the same network and you get duplicate IP address errors.

I hope this helps.

bakunin

1 Like

thanks, it never came across my mind this method although one of the fundamental one in AIX ....

solved.