Fedora and LVM [LWN.net]

Fedora and LVM

Posted Nov 1, 2012 3:41 UTC (Thu) by faramir (subscriber, #2327)
In reply to: Fedora and LVM by dlang
Parent article: Fedora and LVM

>On my servers, I just do two root partitions and install the new OS into the currently unused parition.

That's fine for a fresh install. I believe the use case was for a easily revertable upgrade. Not the same thing.

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Fedora and LVM

Posted Nov 7, 2012 13:00 UTC (Wed) by emmi3 (subscriber, #62443) [Link]

But it's not so much different either. I've ben using this "two primary root partition"-setup for quite some time on all my systems at work. Although I usually prefer to reinstall my desktop systems, this is how I would handle the "revertable upgrade" case:

- create an new filesystem with a different label on the unused partition
- copy the old system over
- change the label for the root filesystem in /etc/fstab to the new one (I would also grep through /etc/ for the old label eg. xubuntu1204, debian60, just in case)
- chroot into the new system and install grub to the new root partition and update-grub (or install and reconfigure extlinux... :)
- activate the new and deactivate the old partition
- reboot

If anything goes wrong just reboot into the old root. Using "MBR" this is a simple matter of pressing the shift-key and choosing the right partition at boot time.

Fedora and LVM

Posted Nov 7, 2012 18:26 UTC (Wed) by faramir (subscriber, #2327) [Link]

That's quite a lot of manual labor for every time you want to do a revertable upgrade. Which if it was easy enough, I think many would want to do for every upgrade.

Setting up LVM (with snapshots for /) might be a bit more difficult during the initial install, but it seems to me it is going to be a lot more convenient in the end.

In either case, you have to have done something up front during the initial install. i.e. Either used LVM or set aside a partition for your second root.