I had installed mandriva first.
I reserved 30GB for opensuse.
Now, is it safe to just install Opensuse and it will autodetect my Mandriva and preserves it in bootloader?

I think it rather over-write it... Should ask about it during the installation though..

Yes, it's safe. It will detect mandriva and add it to bootloader menu. Or you can keep mandriva bootloader (just refuse to install bootloader during installation, then start mandriva, and run update-grub. It will detect your opensuse installation, and add it to bootloader menu.)

can I share Swap partition for both linuxes?

Yes, because only one distribution will be using it at a time. Really, though, you might not even need a swap partition (depending on the amount of RAM you have).

how about the / and /home partition? Both uses the same lable, will it be confused?

What do you mean? You won't want to share the root partition between distributions. You could share the partition on which /home resides, but I'm not sure it's advisable - different distros have different configs (or perhaps just different versions of the same config files) that go in the user's home directory and yes, that could get confused.

Things about Grub you may find interesting.

Grub has a shell that you can invoke that will just have temporary effects so you can experiment with it. You do this while it is booting.You can boot any system with the Grub style shell terminal if you know where it is located as in drive/ partition.

Make a copy of your menu.lst from your current distro and save one as well from your new install on paper so when grub decides to dump one of your O.S's you don't have to reinstall it.Computer>Filesystem>Boot>Grub>menu.lst.Reinstalling your boot loader would not fix it. You can't JUST put grub on it's own partition and have it work. The first stage of grub needs a way to find it. I now this from experience and can't help how to implement it.I wish I did.


May the Linux Deities be with You! Serendipity to All!

If I am correct, both distros use Grub2, so there will be no menu.lst-file. Grub2 is configured with the grub.cfg-file, which is automatically generated from the update-grub command. In any case, if your bootloader "dumps" an OS you do not have to reinstall, it is easy to fix this issues. But in general it is not wrong behaviour to have backups of config files.

is it better to run another linux os in vmware or virtual box?
but that would be slow if ur CPU not fast enough and lack of memory

Better in what way? It's better if you want to have them running at the same time, I guess.

if the CPU and ram is high performance, running in virtualbox is ok.

Have you answered your own question?

Hello TigerLinux,sharing the / partition isn't possible. Sharing the /home partition is possible but not usefull. Im dualbooting Gentoo and Arch and I have a /home partition for every distribution. The Problem with sharing home is that many programs are not in the same version on both distros. I've tried sharing home and experienced great problems with Firefox and Thunderbird. The language addons for this programs often change with every version and are not compatible with older versions.
A workaround could be, to create two minimal partitions for the two homes, e.g. 3GB and create a big partition which is mounted for exampe as /usr/local/public on both distributions. When using the same users with the same password, one can share dokumentes in this folder but the configurationfiles in the .directories in every home are separated.

Markus

This is not recommended as the configuration/desktop files are likely to be different. I would recomment a separate /data partition containing /documents, /pictures, /music, etcetera (personal files) and put soft links in each /home partition. Definately DN NOT use a common "/" as one distro will overwrite the other causing a real mess.

Tom