I'd like to set up a machine to dual-boot Ubuntu and CentOS5. Any problems foreseen with this? I'm mostly worried about disk labeling; they each need their own /boot and / filesystems.
(Or do they need separate /boot partitions? Obviously there's an issue with boot.* and *.b and what System.map is symlink'd to, etc., but maybe there's a way to work around that.)
Bart Schaefer wrote:
I'd like to set up a machine to dual-boot Ubuntu and CentOS5. Any problems foreseen with this? I'm mostly worried about disk labeling; they each need their own /boot and / filesystems.
(Or do they need separate /boot partitions? Obviously there's an issue with boot.* and *.b and what System.map is symlink'd to, etc., but maybe there's a way to work around that.) _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Why dual boot at all? Why not just run a Xen instance?
On Jan 9, 2008 2:49 PM, James A. Peltier jpeltier@cs.sfu.ca wrote:
Why dual boot at all? Why not just run a Xen instance?
I knew someone was going to ask that ...
I'm only planning to dual-boot while I determine which operating system to leave on the machine permanently. I don't want Xen masking interactions with the hardware in a way that might give different results from the actual behavior of each OS on the raw machine.
On Wed, 09 Jan 2008 15:03:39 -0800 Bart Schaefer barton.schaefer@gmail.com wrote:
I'm only planning to dual-boot while I determine which operating system to leave on the machine permanently. I don't want Xen masking interactions with the hardware in a way that might give different results from the actual behavior of each OS on the raw machine.
I set up a machine that booted 4 different Centos installations the other day.
All you have to do is tell the installer that you want to do a custom partitioning scheme, then point it to /dev/sda or /dev/sdb or whatever, and tell it to use X amount of the space on that drive. Don't install the boot loader on anything but the first install, then add the new partitions/setups manually to grub.conf as you create them.
I found it easiest to not use a /boot partition though there is probably a way to do it with one as well.
Here is the grub.conf that I ended up with on my 4-way booting machine:
# grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You do not have a /boot partition. This means that # all kernel and initrd paths are relative to /, eg. # root (hd0,0) # kernel /boot/vmlinuz-version ro root=/dev/sda1 # initrd /boot/initrd-version.img #boot=/dev/sda default=0 timeout=5 splashimage=(hd0,0)/boot/grub/splash.xpm.gz hiddenmenu title HomeComputer (2.6.18-53.1.4.el5PAE) root (hd0,0) kernel /boot/vmlinuz-2.6.18-53.1.4.el5PAE ro root=LABEL=/ rhgb quiet initrd /boot/initrd-2.6.18-53.1.4.el5PAE.img title AnsweringMachine root (hd0,3) kernel /boot/vmlinuz-2.6.18-53.1.4.el5PAE ro root=/dev/sda4 rhgb quiet initrd /boot/initrd-2.6.18-53.1.4.el5PAE.img title ApplicationServer root (hd1,0) kernel /boot/vmlinuz-2.6.18-53.1.4.el5PAE ro root=/dev/sdb1 rhgb quiet initrd /boot/initrd-2.6.18-53.1.4.el5PAE.img title WebServer root (hd1,1) kernel /boot/vmlinuz-2.6.18-53.1.4.el5PAE ro root=/dev/sdb2 rhgb quiet initrd /boot/initrd-2.6.18-53.1.4.el5PAE.img
Thanks (and thanks, too, to Tru, which I forgot to say in my previous response).
On Jan 9, 2008 3:14 PM, Frank Cox theatre@sasktel.net wrote:
All you have to do is tell the installer that you want to do a custom partitioning scheme, then point it to /dev/sda or /dev/sdb or whatever, and tell it to use X amount of the space on that drive. Don't install the boot loader on anything but the first install, then add the new partitions/setups manually to grub.conf as you create them.
That's interesting and sort of what I was looking for ... but I'm a wee bit concerned (being an old lilo guy and not very familiar with grub yet) that in fact all those references to /boot/initrd.* and /boot/vmlinuz* really are loading the same instances from the initial install, and that I'd be in trouble when the installs are not both the same linux distribution and version.
Can anyone allay my worries?
On Wed, 09 Jan 2008 20:09:04 -0800 Bart Schaefer barton.schaefer@gmail.com wrote:
I'm a wee bit concerned (being an old lilo guy and not very familiar with grub yet) that in fact all those references to /boot/initrd.* and /boot/vmlinuz* really are loading the same instances from the initial install, and that I'd be in trouble when the installs are not both the same linux distribution and version.
Read my grub.conf, carefully.
Notice, in particular, the NOTICE at the top:
# NOTICE: You do not have a /boot partition. This means that # all kernel and initrd paths are relative to /, eg. # root (hd0,0)
Now, further notice that the "root(hd?,?) entries throughout the grub.conf file are all pointing to different places.
On Wed, Jan 09, 2008 at 03:03:39PM -0800, Bart Schaefer wrote:
On Jan 9, 2008 2:49 PM, James A. Peltier jpeltier@cs.sfu.ca wrote:
Why dual boot at all? Why not just run a Xen instance?
I knew someone was going to ask that ...
I'm only planning to dual-boot while I determine which operating system to leave on the machine permanently. I don't want Xen masking interactions with the hardware in a way that might give different results from the actual behavior of each OS on the raw machine.
I am multibooting my laptop with the following setup:
* I keep a standalone small /boot (primary partition) with grub which is booted by the MBR. * one primary goes for NetBSD * one primary goes for XP * all the other linux distributions (FC8/C5) are on their own logical partition (one single 8GB slice for / including the distribution's own /boot and /home) the distribution bootloader goes to the logical partition. * a swap partion and a "/shared" ext3 partition are shared for all the linux distribution
Cheers,
Tru
On Jan 9, 2008 3:26 PM, Tru Huynh tru@centos.org wrote:
- I keep a standalone small /boot (primary partition) with grub
which is booted by the MBR.
So what files are in that /boot? Just the "grub" subdirectory? Is that partition actually mounted as a filesystem on /boot in any of the linux installs?
Bart Schaefer wrote:
On Jan 9, 2008 3:26 PM, Tru Huynh tru@centos.org wrote:
- I keep a standalone small /boot (primary partition) with grub
which is booted by the MBR.
So what files are in that /boot? Just the "grub" subdirectory? Is that partition actually mounted as a filesystem on /boot in any of the linux installs?
Files that go in /boot are usually just kernel images, their related initial ramdisk images and grub related files.
As naming of kernels between Centos and Ubuntu are very likely to be different, having the two installations to share a /boot should not be a problem.
I suggest first installing one of them and then making a copy of the menu.1st|grub.conf file in case the installation of the second OS just overwrites it. If it does get overwritten, you can copy the relevant lines for the first installation from the copy.
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Bart Schaefer -
Christopher Chan -
Frank Cox -
James A. Peltier -
Tru Huynh