Upgrade advice

[Rick Stevens]

On 10/30/2015 12:12 PM, Jeffrey Ross wrote:
>> On Fri, 30 Oct 2015 10:20:44 -0400 "Jeffrey Ross" <jeff at bubble.org> wrote:
>>
>>> I'm looking for some suggestions on how to upgrade an older Fedora
>>> system
>>> and keep as many of the configurations as possible for the applications
>>> that are being used.
>>
>> The recommendation is to go through successive upgrades one after the
>> other. However, I am very doubtful that one of these will not break. I
>> seem to recall that F18 or F19 was the one which broke upgrades (I think
>> it was F19).
>
> I'm aware of the recommendation to go through successive releases, the
> problem is I can't even get to Fedora 17 because / and /usr are split into
> two different file systems.
>
>>
>>> Currently the system is running Fedora 16 and there are at least two
>>> things that are preventing me from successfully running fedup or the yum
>>> upgrade.
>>>
>>> The first stumbling block is that system was installed with separate
>>> partitions for /, /boot, /var, & /usr and I think that the separation of
>>> / and /usr is my biggest issue.
>>
>> I don't see why this should be an issue in a clean install. Are you
>> wanting to keep /usr because you installed programs here? You may consider
>> moving files that you created to a separate directory inside your home
>> partition and then pushing it back. One possibility is to partition the
>> current /usr and then move the programs to that new partition and keep
>> that one in a new install.
>>
>
> I would rather avoid a clean install if at all possible, of course I may
> not have a choice if I want to upgrade.
>
> The current recommendation (requirement?) is that / and /usr be the same
> partition, I'm pretty sure the problem with /usr being its own partition
> is the location of /usr/sbin and /usr/bin both of which aren't mounted
> when the upgrade is attempted.

Yes, that's precisely the issue.

> I came from the real old school where everything had its own partition,
> today this isn't the best way to do things and now I have a "broken"
> system when it comes to upgrading.
>
>>> The second issue is the system is setup with RAID1 on all partitions with
>>> the bootloader (Grub ?) installed on both disks in the event of a disk
> failure.
>>
>> I am not sure how RAID0 figures into this equation: I have not much
>> knowledge of this, sorry.
>
> I think there were some issues with using RAID on the boot partition but
> I'm not positive.

Conversion from a separate / and /usr is fairly easy--provided your 
current "/" filesystem is large enough to accommodate the /usr content.

Assuming that "/" is on /dev/md0 and "/usr" is on /dev/md1, after you
boot the live system in "rescue" mode:

	1. Make sure you have two spots to mount this stuff on the live
	system:

		# mkdir /mnt/oldroot
		# mkdir /mnt/oldusr

	2. Mount the old "/" to "/mnt/oldroot", e.g.:

		# mount /dev/md0 /mnt/oldroot

	3. Mount the old "/usr" to "/mnt/oldusr":

		# mount /dev/md1 /mnt/oldusr

	4. Copy the entire /usr stuff to the old root partition:

		# cp -a /mnt/oldusr/* /mnt/oldroot/usr

	5. Once that's done, comment out the /usr mount by editing the
	fstab on the old root partition:

		# vi /mnt/oldroot/etc/fstab
		(delete or comment out the mount for /usr)

That should do it. If you reboot the system, it should have been
converted over. Note that you haven't destroyed the old /usr partition.
If you need to revert, just boot up in rescue mode off the live system
again and:

	1. Mount the old "/" at the normal rescue mode mountpoint:

		# mount /dev/md0 /mnt/sysimage

	2. Delete the CONTENT in the /usr directory on the old /
	filesystem:

		# rm -rf /mnt/sysimage/usr/*

	3. Edit the old fstab and re-enable the /usr mount:

		# vi /mnt/sysimage/etc/fstab

Reboot and everything should be back to what it was.

If you don't have enough root on "/" to accommodate the /usr content,
that's a different kettle of fish.

As to the issue of the boot loader on both disks of a RAID1, that has
to do with using a software RAID1. grub2 (as present on F22) is RAID
aware but does have a requirement that there be a 1MB space between the
MBR on the drives and the first partition (e.g. if you us a 512-byte
sector size, then the first partition must start on or above sector
2048). This space is used for the "core.img" file.

Note that when you install grub2, you must specify BOTH of the drives
involved in your RAID1. If you are only able to install to one of them
(say, /dev/sda), once the system is booted you can "grub-install 
/dev/sdb" to put it on the second drive.

You're playing with fire here and it's really easy to get burnt to a
crisp! Before you do ANY of this, make damned well certain you have a
current backup of EVERYTHING and that that backup can, indeed, be
recovered from. Many people do backups but never test the recovery and
if you can't recover, then the backup is less than useless.

For bare-metal backup and recovery, I use Mondo Rescue to create DVD
ISO images and store them on a USB hard drive, but use whatever you
like. Just make sure it works.
---------------------------------------------------------------------
- Rick Stevens, Systems Engineer, AllDigital    ricks at alldigital.com -
- AIM/Skype: therps2        ICQ: 226437340           Yahoo: origrps2 -
-                                                                    -
-           If it's stupid and it works...it ain't stupid!           -
----------------------------------------------------------------------