Planning dual boot F8 and F9

[thunderogg]

I'm finally getting rid of my LVM. :) I would like to dual boot F8 and F9. After having looked in the forum and this is what I have in mind:

One /boot partition, one /home partition shared between F8 and F9, but with different users not to screw up the settings. Then I need two / partitions on about 15GB each with a swap on 4GB.

To my questions.

1. Which partitions should be primary partitions--the /boot maybe, any else?

2. Can F8 and F9 share one swap partition?

3. Can I create all partitions when I install the first (F8), or do I have to wait with creating the partitions that will be used for the second installation? (Silly question maybe.)

Other suggestions are welcome.

[thunderogg]

OK, I found more things. There's a lot of info around here. :)
I have changed some things. I will put first Grup in MBR and the second in the /. See post:
http://forums.fedoraforum.org/forum/showpost.php?p=994189&postcount=3
Then I will create two swap partitions of 2 GB to avoid problems with Ubuntu. (if I get around to install it)
Thanks, Bob, for that info!

[drunkahol]

What do you find wrong with LVM?

Cheers

Duncan

[thunderogg]

Eh, there's nothing wrong with it. It's just that I feel more comfortable with clean ext3 partitions I can use gparted on.

[thunderogg]

Hm, how can I be sure the installer program won't format the /home partition when I install the second system? The /home partiton already contains information I don't want to loose.

[mattcen]

It should ask for confirmation before formatting any partition, particularly if you partition manually. You have to explicitly select 'format' on the partitions you want formatted.

Regards,
Mattcen

[thunderogg]

It should ask for confirmation before formatting any partition, particularly if you partition manually. You have to explicitly select 'format' on the partitions you want formatted.

Regards,
Mattcen

OK, that feels comforting. Thanks! :)

[forkbomb]

OK, that feels comforting. Thanks! :)
Just a couple things:
No problem in sharing swaps between two distros. I've done it before, I'm doing it right now, and I have not and do not have any problems now with sharing swaps. The only reason you might want two swaps is if you want for some reason two different sized ones, and then you might as well just make a single big one...

I'd be much more concerned about sharing home partition, at least unless you use different usernames, as the distros are going to "fight" over config files and possible bork one another. Shouldn't be a problem if you go with two different usernames, but then you'll probably want to store shared stuff on /home/yaddayadda instead of in /home/username because permissions will be weird (if your user in distro a is "bob" and your user in distro b is "smith" bob won't be able to read stuff under /home/smith and vice versa unless you do some chowning every time you boot up into one or the other). I've tried sharing a home partition or reinstalling a different version or OS without formatting home and it caused problems. These days I don't make a partition for /homes, but instead use /mnt/stuff for a shared partition (yup, that's the actual mount point I use ;) ) and then mount it to the proper uid in both OSs.

Instead of mounting the /home from your first OS as /home in your second install, consider mounting your /home from the first as /mnt/data or something like that in the second one.

[thunderogg]

Just a couple things:
No problem in sharing swaps between two distros. I've done it before, I'm doing it right now, and I have not and do not have any problems now with sharing swaps. The only reason you might want two swaps is if you want for some reason two different sized ones, and then you might as well just make a single big one...

I read somewhere that someone had some problems with Ubuntu, and maybe I one get around to try it. Eh,why would I do that? Fedora just works! Anyway, it's not a big deal, 2 or 4GB. I can live with that.

These days I don't make a partition for /homes, but instead use /mnt/stuff for a shared partition (yup, that's the actual mount point I use ;) ) and then mount it to the proper uid in both OSs.

This was an excellent idea! It's much safer! No need to worry about loosing the info. I wanted a big partition for my mp3s, that I could share between the distros, and also use a way to copy things between the two. Hm. if I only had thougt about that. I already have a separate /home partition and Fedora 8 running beautifully. Can I unmount that /home partition and create a /home directory in the / partition on the fly? :rolleyes:

[thunderogg]

Well, I can do it if I switch off the modem, and log in as root.

[forkbomb]

I read somewhere that someone had some problems with Ubuntu, and maybe I one get around to try it. Eh,why would I do that? Fedora just works! Anyway, it's not a big deal, 2 or 4GB. I can live with that.



This was an excellent idea! It's much safer! No need to worry about loosing the info. I wanted a big partition for my mp3s, that I could share between the distros, and also use a way to copy things between the two. Hm. if I only had thougt about that. I already have a separate /home partition and Fedora 8 running beautifully. Can I unmount that /home partition and create a /home directory in the / partition on the fly? :rolleyes:
Sure, you can. I've done it before but it was a bit of a pain in the butt. You shouldn't do it while logged in as the user whose home your are moving (it'll likely crash out your session). Best is to log into a GUI session as root (Fedora will squack but tell it to chill out for a minute) or do it from a TTY (I did when I did the move). The general steps from what I remember:
1) Log in as root
2) unmount the /home partition
3) edit /etc/fstab to change the /home mount point to your new data mountpoint, whatever that may be. Create the mountpoint as root (mkdir /my/mount/point - keep in mind that you can't mount a partition to a non-existent mount point).
4) Mount the old /home partition at the new mount point.
5) Copy over anything from the old home at the new mount point to the regular home (the new home) on the root partition that you want for personal config files. Most of these are hidden (start with a .). Anything you want to keep in the "slush space" that you'll be sharing can be left (e.g. your mp3 library). If this sounds confusing, you can skip it, but you'll have to reconfigure stuff that's related to your personal regular user account (for instance, firefox bookmarks and stuff) which isn't necessarily a huge deal. (Config files for single users are often under /home/username/.someapp)
6) Think that should be it... back up your data before fiddling with any partitions, of course. Once you log in and verify your user's account is working with the old config files, you should be able to reorganize your former home however you see fit including deleting old config files from that old partition.

As far as I can tell you shouldn't even need a reboot.

I've also done this the other way... moving my /homes on the / partition to a separate partition. That's a little more work and a bit more complicated. :p

[thunderogg]

Good, will do it tomorrow! Thanks a lot! :)

[thunderogg]

3) edit /etc/fstab to change the /home mount point to your new data mountpoint, whatever that may be. Create the mountpoint as root (cc- keep in mind that you can't mount a partition to a non-existent mount point).


Do I really need to mount /home on another existing directory? Can't I just: mkdir /home direct and remove the /home line from fstab? Maybe that's windowish ... :)

[stevea]

1/ You can share swap - the only downside is that your suspend storage is in swap - so if you boot A, hibernate, reboot B ... you've probably lost your suspended session+OS. Not a big issue to me.

2/ I don't see problems using shared /home, but I'm using comparably current OSes and don't mind a few issues w. the ~/.gconf files and such. If that's a big issue than by all means use separate /home and then use the another link for the desktop. One of the pam_ method session modules will do the automount or create a link (don't recall which at the moment).

3/ You really don't need a separate /boot if you are using an bootable file system type like /ext3 or (maddog) reiserfs (grub can handle 10 different file systems) but yo udo need a separate boot per Distro. Just make one biggish (say 10-20GB) partition for each distro and leave the /boot (and perhaps /home) there. The user data (Desktops) can reside elsewhere if you wish.

Why is everyone so antsie about different <UID.GID>'s on different OSes. The answer is to never allow these to change across systems. This solves local mount and also NFS mount issues.

I have a script like:
groupadd -g 520 ricci
groupadd -g 521 lucy
groupadd -g 522 fred
groupadd -g 523 ethel
# ignore warnings
adduser -u 520 -g 520 -G 599 -c ricci ricci
adduser -u 521 -g 521 -G 599 -c lucy lucy
adduser -u 522 -g 522 -G 599 -c fred fred
adduser -u 523 -g 523 -G 599 -c ethel ethel
--
So I use the identical UID,GIDs on al local systems.
It's so mindlessly easy if you just set things up correctly at the start

*WHY* would you ever permit the same account to have different UIDs ?
.

[forkbomb]

Do I really need to mount /home on another existing directory? Can't I just: mkdir /home direct and remove the /home line from fstab? Maybe that's windowish ... :)
You don't really need to do mkdir /home. Here's why - the directory or mount point already exists. But the problem is the matter of what devices are currently associated with the mount point. Think about how mount points work. If you have a specific partition mounted to /home, it's telling the kernel that any reads/writes that refer to /home are supposed to read from/be written to that partition. If you want to access those files on your current home, and move your current /home to the root partition, yes - you're going to have to put the partition with your current /home on a new mount point if you want to, say, have your music accessible (I assume right now your music is at /home/yourusername/Music or some such thing). Say you have a partition /dev/sda3 for the sake of argument, and say that's your current home (the one you want to mount to /share).

If you remove the line from /etc/fstab that mounts /dev/sda3 to home, your home will essentially be empty now because the kernel won't be looking to that partition any more.

Don't know how else to explain it. :confused: Hope I'm not misreading the question. :(

[stevea]

To follow up on tjvanwyk's point (as I read it). If you tell the installer to create a separate /home partition then it creates an empty /home directory on "/" where we then mount the other partition. If we do NOT tell the installer to use a separate partition for home, then there is still a /home directory but it is in turn used to hold /yourname directories and contents like /home/yourname/Music (all on the root "/" partition).

So no. You don't need a separate /home.on a separate partition, but it's a good idea for a lot of reasons.

[thunderogg]

tjvanwyk and stevea, I've been reading your answers a couple of times. I'm a slow thinker. :) Thanks a lot for your views and advice. Will see what I can make of it today.

[thunderogg]

OK, I now have /home in the / partition. I copied the existing user directory from the old /home partition to the present /home. I logged in as that user and everything works fine. My only problem is to relabel the old /home partition from /home to let's say /share. I mounted the old /home on /mnt/share but when it appears on the desktop it says /home. It looks a bit confusing.
I looked in gparted but only found Device->Set Disklabel ... That seems to relabel the whole disk, or? I just want to relabel a partition. Can't I do that?

[thunderogg]

Solved with e2label /dev/sda2 /share