UNIX for Dummies Questions & Answers

Hi, Currently running Redhat 5.8, I am thinking about upgrading to 6. After the upgrade, in case, I want to downgrade. How would I do that?

Please let me know. Thanks.

IMHO it is not wise to downgrade you are looking for serious issues...
So it leaves you with check all your backups, do a last one, I am paranoid so I check my system backups by restoring things... or checking if its bootable etc...
If you have a system disk in mirror, then you could split the mirror and upgrade...
And use the second to reboot in previous version or resync when all is validated (that is mostly what I do but not all use dedicated disks for OS and mirror them...)

Always make a good, reliable backup in case you do want to revert back to the old version. There is no other reliable way to downgrade any OS I've worked with (OS X is the closest, but RH is definitely out).

The best way I've known to do this is image to another volume with 'dd' if you have the space on a separate volume, or adding in netcat if not. To save space you can fill your drive out with zeros before hand so it will compress easily The Digital Voice: DD over Netcat for a Cheap Ghost Alternative has a good discussion on this. To zero out the drive before hand, boot off a live CD of some kind, mount the filesystems on the drive you're imaging and run something similar to

Code:

dd if=/dev/zero of=/mnt/mountpoint/fill && rm /mnt/mountpoint/fill