cant mount ext4 partition from redhat

[aksoni]

i hv 3 os installed ...windows7,ubuntu9.10 and redhat5.3
can ne1 tell me how to mount ext4 partition from redhat....because after installing redhat ubuntu is not booting....or can ne1 tell me how can i boot ubuntu by editing grub.config???

[Rubberman]

What errors are you getting when you try to boot ubuntu? FWIW, Ubuntu and RHEL use different versions of grub, so the problem is likely due to the order you installed them in. You probably will need to install grub2 in order to sort out the booting problems. I haven't played with it enough to do anything more than to suggest this. Other lurkers/advisors on this forum may be more helpful in that regard.

As for mounting ext4 on RHEL, it depends upon the kernel you are running. They didn't add ext4 support until the 2.6.18-128 kernel which was sometime in the middle of last year. The command uname -r will tell you which kernel you are running.

[Rubberman]

From the Red Hat web site about ext4 support:

ext4
The latest generation of the ext filesystem, ext4, is available in this release as a Technology Preview. Ext4 is an incremental improvement on the ext3 file system developed by Red Hat and the Linux community. The release name of the file system for the Technology Preview is ext4dev.
The file system is provided by the ext4dev.ko kernel module, and a new e4fsprogs package, which contains updated versions of the familiar e2fsprogs administrative tools for use with ext4. To use, install e4fsprogs and then use commands like mkfs.ext4dev from the e4fsprogs program to create an ext4-base file system. When referring to the filesystem on a mount commandline or fstab file, use the filesystem name ext4dev.

The web page this is found on is here: 7.*Technology Previews

[aksoni]

for booting ubuntu there is no any option shown when i boot up my system.....
after that i chage boot.config of redhat by appending some code of menu.lst of ubuntu......though i cant boot ubuntu...................
i want to access data from ubuntu dev/sda10 partition any way .....by booting ubuntu or by mounting dev/sda10 ext4 partition from redhat5.3...or from windows....how can i do??

[Rubberman]

First, make sure that you have a current kernel that is 2.6.18-128 or later. Next, install the e4fsprogs package. Then you should be able to mount the file system in the normal way as in mount -t ext4dev device mount-point where 'device' is something like /dev/sda1 and 'mount-point' is an empty directory on your system. If the type ext4dev doesn't work, then try ext4 by itself. The fact of the matter is that ext4 is still "experimental", in final development, and not recommended for enterprise systems as yet.

[mrkoconnell]

I am running several versions of Linux on different machines and the only one with ext4 is a recent Ubuntu with kernel 2.6.31-14. I looked up ext4 after reading your post and found that ext3 is only partially forward compatible. However ext4 is backward compatible to ext2. Could you open the version with ext4 and see if you can mount the other partitions? Also try checking filesystems with $cat /proc/filesystems.

[glennzo]

If you can't boot Ubuntu using Redhat's bootloader then you'll probably need to reinstall Ubuntu's bootloader. The newer Ubuntu's use grub2 and I don't believe grub 1.97 (or whatever Redhat is using) can boot a system using grub2. If you reinstall the Ubuntu bootloader it will likely pick up on the fact that Redhat and Windows are installed and automatically add them to the menu. If not, it can be done manually.

I recently reinstalled Ubuntu 9.10's bootloader on a system that boots several Linux variants. I used the following 2 links as guides.
Grub 2 Basics - Ubuntu Forums
https://help.ubuntu.com/community/Gr...ing%20GRUB%202

It worked extremely well for me. Remember to "forget" everything you know about grub 1.97. Not even close.

[peteh]

You can boot Ubuntu on ext4 from Grub legacy. Just put a new entry in your menu.lst.
Yoou need the title (Ubuntu?), the partition where grub lives (hd0,0 ?) the kernel image and ubuntu root partition and the initrd image.
So it would look something like this

title  Ubuntu
root (hd0,0)
kernel /boot/vmlinuz-2.6.xxx root=/dev/sda1
initrd /boot/initrd.img-2.6.xxx

You may want additional parameters in the kernel line and of course you would change the 2 partitions to the correct ones but that should do it.