[Discuss] --sandbox switch for Ubuntu's do-release-upgrade/update-manager

[richard.pieri at gmail.com (Richard Pieri)]

On 3/9/2015 4:03 PM, Matthew Gillen wrote:
> I think I'm convincing myself that if you want to roll back, use VMs.
> /boot is too complicated to deal with.

No, you have the right idea. It's possible to roll back with LVM but the 
problem with this is that you /must/ eventually roll back or re-create 
the file systems else you'll eventually run out of space in the volume 
group. This is the same problem that AUFS and other union (overlay) file 
systems have. They're not file systems as we typically think of them. 
They're logs of transactions relative to a master file system.

Ubuntu has a long history of not being upgradable in place. Ubuntu uses 
Debian's package management system but it doesn't use Debian's stability 
mandate. That's Debian's definition of "stability" which more or less 
means "updates and upgrades never break a working system."[1] That 
Ubuntu's Johnny-come-lately upgrade tool needs a sandbox mode is 
demonstrable proof of how poor it is in its current state. Personally, 
on the rare occasions where I have to do a major upgrade on Ubuntu I 
make sure that my configuration documents are in order, I do a clean 
install, and I recreate the custom configuration based on the documentation.

[1] I've only once encountered a situation where Debian was required to 
break that mandate and that was due to a security change in Dovecot up 
stream that broke everybody.

-- 
Rich P.