Linux-Linux dual boot ?

[narayanan]

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Am not an absolute beginner. Have tried Redhat, Debian, Madrake and Ubuntu in the past as a dual boot with Windows. Now I want to complete take Windows out of my system, I was wondering:

1. If I can dual boot 2 different distros of Linux ?

2. Assuming I am starting off with a completely unpartitioned system, how do i partition when installing my first distro ? and how would I do the second?

3. I have about 17 GB of HD space, thinking of allocating around 5GB for each distro and 7GB of data that can be used by both distros. In that case how do i assign mount points ? Also can there be shared resources such as swap space between the 2 distros ?

4. Where would I be writing GRUB when I install the first distro and what about the second ? Are they going to be on the MBR or /boot shared between the 2 distros ?

The first distro I have decided on is Debian, thinking of Slack/Gentoo on the other, have left that for later.

If there is any link relating to such an installation, it would be really great. Thanks.

[Wraithe]

ok...firstly i run 2x distro's of linux and win xp...the grub installer is on my second distro and i have had to do some hacking to get it to work right...
mostly give it the right directions really..its in /boot/grub and you have to make sure menu.lst is configured correctly...dont stress as it is repairable if you cant boot to the other distro...i would install the first and then do the same with the second and then repair the boot loader...install to mbr...very little actually goes there....
i have one swap partition and not so long ago had 5x distro's all using the one swap partition....if you use a partition for sharing, well i dont but name it anything that is not a standard directory name...i dont know how you would go naming it as home, and whether it would share it...
could use win or something you wont use else where...
best of luck...as for a link about this...hmmm...i dont have any at hand but look up duel boot or grub/lilo and they should tell you...linux installed first and then another linux distro is no diff to win first then linux...same stuff applies basically...there is no limit to how many distro's you can install and boot, except maybe your pockets...

[antidrugue]

There is simply no limit in how many distros you can install on one machine. You can dual, triple, quadruple boot, etc.

Check out this example, with more than a 100 linux distros installed on the same system:

http://www.justlinux.com/forum/showthread.php?t=143973

[narayanan]

100 :o thats too much. anyways am restricting myself to just 2 due to lack of space. I am planning to partition this way:

/hda1 - 4.7 GB - root for the first distro
/hda2 - 4.7 GB - root for the second distro
/hda3 - 7 GB - /share that would share data between distros, I dont plan to install any packages here.
/hda4 - 500 MB - swap, thats common between the 2.

Would this do i need to create a seperate /boot ?

[antidrugue]

100 :o thats too much. anyways am restricting myself to just 2 due to lack of space. I am planning to partition this way:

/hda1 - 4.7 GB - root for the first distro
/hda2 - 4.7 GB - root for the second distro
/hda3 - 7 GB - /share that would share data between distros, I dont plan to install any packages here.
/hda4 - 500 MB - swap, thats common between the 2.

Would this do i need to create a seperate /boot ?

The beginning of the harddrive is always faster. SWAP needs to be fast. Plus your OS will boot faster with a separate boot partition.

/hda1 - 100 mb - boot for 1st distro
/hda2 - 100 mb - boot for 2nd distro
/hda3 - 500 mb - SWAP
/hda4 - 4.7 GB - root for 1st distro
/hda5 - 4.7 GB - root for 2nd distro
/hda6 - 7 gb - /share

Something like that. Anyway pretty much anything will work.

Your scheme is good too, you could just switch SWAP with /share.

[Roxoff]

You might consider allowing both the distros share the same /boot partition, that way they'll both write their kernels into there, and they'll share the same /boot/grub/grub.conf - which might make things a little easier when one of them installs an upgraded kernel and needs to make an entry for it in that file.

[narayanan]

Just a few clarifications:

When I install my first OS, it would'nt ask for grub options? or if so, I put it in the MBR?

Same thing with 2nd OS, I know it would ask for booting options now, but do i write on MBR or /boot now ?

[Roxoff]

Grub normally goes on the MBR. You'd only put it on a partition if you were trying to set up special boot scenarios, or trying to use the windows boot loader.

When you install the 2nd OS, make sure you dont format the /boot partition. The grub install for the 2nd os should detect the other system and set itself up accordingly, but if it doesn't you dont have too much to worry about - you can either fix the grub.conf by hand, or even go as far as re-installing the 1st os.

[coplan]

Roxoff's advice about having the same boot is a very good one. One caveat to it though...don't overwrite your kernels between distros. If you copy the kernels manually after they are compiled, you can name them whatever you want. I prefix mine with distro name. Example: gentoo-2.6.13-gentoo-r7 (fyi, I used the gentoo patched kernels...so it's not really redundant -- first 'gentoo' tells me I compiled it for gentoo.)

As for your partition mounted on /share -- to keep with Linux System Base standards, I recommend you mount this at /home. All your user directories are there, and you can maintain the same user-space between them. If you absolutely want separate homes...I recommend sticking your shared drive as /opt. No reason to create an addition to the tree.

[narayanan]

I finally managed to get Debian and Gentoo installed. First installed Debian on hda1, followed by Gentoo (although the installation broke about 5-6 time before i just chose gnome, xpdf and emacs as the only packages while doing a command line install from the livecd). The partitioning is as follows:

/hda1 6GB - Debian root
/hda2 100 MB - Gentoo boot
/hda3 6GB - Gentoo root
-extended 7 GB
hda5 - 500MB swap - common to both.
rest still unpartitioned

I still have 2 questions:

1. I am planning to use the unpartitioned space just to put some documents, media files which can be used by any user. So does it make sense to mount it as a /home partition still ?

2. While booting I wrote the GRUB menu once while installing Debian and write again when installing Gentoo. My question here is..why does it show grub loading twice before it shows the grub menu ? although it isnt a serious problem, just curious how to avoid it.