vxvm downgrade from 5.0 to 4.1
There is once a time that I was tasked to downgrade vxvm from 5.0 to 4.1, after the downgrade, all dgs are unable to import with some invalid configuration. After gone through all the relevant document, I couldn't fnd any references. After open a case with symantec, I got the finial confirmation this is not supported and data backup & restore must follow the downgrade of binary vxvm software.
Having said that, my task was still there, without being supported, I still need to action this task and after several tests, it went through. Pls note, this is NOT supported by symantec and you should NOT try this on production environment with proper backup in place. Make a backup either from application level like file system level, or from lower level like disk level with such as EMC bcv etc etc.
Ok, let's walk through the procedure and you might provide a better sub steps, if so, pls contribute to this community to make life easier for any others who got the same task.
step 1. backup the current dg configuration
vxprint -Qqmhspv -g <dgname> > dg.txt
of course, do a verification with below command
vxprint -D - -ht < dg1.txt
step2. check disk name
vxprint -qd -g <dgname>
step3. destroy dg, pls note this step is done under vxvm 5.0.
vxdg destory <dgname>. by this stage, the actual data is still on disk, but the vxvm configuration got deleted.
step4. downgrade vxvm software from 5.0 to 4.1
The procedure is quite straight forward. With install/uninstall script provided with storage foundation, you first delete vxvm 5.0, then install 4.1
step 5. verify configuration dg.txt, under vxvm 4.1
vxprint -D - -ht < dg.txt
Certainly you will get bunch of error in saying some configration items are not valid, because they are supported under vxvm5, but not 4.1
What you need to do is delete below configration items from dg.txt
By this point, the configration dg.txt should be accepted by command
vxprint -D - -ht < dg.txt
step 6. recreate dg
vxdg -T 110 init <dgname> <disk mapping>
for disk mapping, pls refer to the output from step 2 above
step.7 recreate volume with configuratin dg.txt
vxmake -g <dgname> -d dg.txt
step.8 the very last step is to start the volume
vxvol -g <dgname> init active <volume name>
mount /dev/vx/dsk/<dgname>/<volume name> <mount point>
At this stage, you now got all the data back under vxvm 4.1
Pls note. I moved this procedure from my another personal blog to this community with some slight changes, if you see one blog very similar, that is possiblly mine.