What Fedora makes sucking for me - or why I am NOT Fedora

[Les Mikesell]

Stefan Held wrote:
> Am Mittwoch, den 10.12.2008, 14:29 -0600 schrieb Les Mikesell:
> 
>> I'm not sure how practical that would be unless you could still mount 
>> and access the updated version after reverting.  Suppose you've done 
>> several days work before you trip over the showstopper bug that makes 
>> you want to revert.  Or the update makes format changes that aren't 
>> backwards compatible in files on other partitions?
> 
> This is more than practical :)
> 
> To be honest, the solaris guys are doing this recently. Take a snapshot,
> apply the updates. If something is wrong you can move backwards and
> forwards in the snapshots for the root partition.
> 
>> I'd go for an option to install a spare matching partition for the 
>> system and have updates always rsync the previous to it before changing 
>> anything (both partitions always mounted, no lvm magic) but even that 
>> doesn't cover everything that can go wrong.
> 
> This solution would be best with splitting /home into a own lvm
> partition. I never heard of a system update breaking something serios
> in /home :)

I think that means you've never tried running multiple versions with an 
nfs mounted home.  All sorts of things twiddle their dot-files with 
changes that older copies don't like.  So once you have run the new 
version of a program you may not be able to go back.

> Your solution would use to much space in my opinion. 

Disk space is cheap in most cases - and regardless, an LVM would have to 
have space for the snapshot and it's cheaper than maintaining a separate 
test machine or VM image.  And as an option, anyone who didn't want it 
wouldn't have to.  The main downside I see is that you'd have to decide 
up front how big the system can grow and allocate 2 of them.

I do think it is better to focus on how to avoid breaking important 
machines in the first place - and that necessarily involves breaking 
more unimportant ones, but this could be another safety net.

-- 
   Les Mikesell
    lesmikesell at gmail.com