Hi we installed centos on a Intel server board with LSI rad (no raid configured for the lsi). in Centos it sees both drives so we software raid them and the installation goes well and finishes properly. The problem is when the server reboots it can no longer see the hard drives and no just boots to a low level diagnostic shell. Any ideas?
Thanks
- Nathan - http://www.netdigix.com
On 15/02/06, Nathan lists@netdigix.com wrote:
Hi we installed centos on a Intel server board with LSI rad (no raid configured for the lsi). in Centos it sees both drives so we software raid them and the installation goes well and finishes properly. The problem is when the server reboots it can no longer see the hard drives and no just boots to a low level diagnostic shell. Any ideas?
Is the diagnostic shell single user mode? That would lead me to think the kernel's bootstrapping to some extent at least and seeing the disks otherwise where that shell coming from? Unless it's the grub shell?
What does ...
# fdisk -l
... list if it runs? Can you boot into rescue mode from an install CD, does it find the installed OS and allow you to chroot into it? If not does fdisk see the disks at this level?
If it's not getting further than greb then it's likely there's no support for the disk controller in the initrd installed in boot but there is in the one used off the CD.
Will.
no its the prompt centos goes to when it cannot find anything to boot to.
thanks
Quoting Will McDonald wmcdonald@gmail.com:
On 15/02/06, Nathan lists@netdigix.com wrote:
Hi we installed centos on a Intel server board with LSI rad (no raid
configured
for the lsi). in Centos it sees both drives so we software raid them and
the
installation goes well and finishes properly. The problem is when the
server
reboots it can no longer see the hard drives and no just boots to a low
level
diagnostic shell. Any ideas?
Is the diagnostic shell single user mode? That would lead me to think the kernel's bootstrapping to some extent at least and seeing the disks otherwise where that shell coming from? Unless it's the grub shell?
What does ...
# fdisk -l
... list if it runs? Can you boot into rescue mode from an install CD, does it find the installed OS and allow you to chroot into it? If not does fdisk see the disks at this level?
If it's not getting further than greb then it's likely there's no support for the disk controller in the initrd installed in boot but there is in the one used off the CD.
Will. _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Thanks
- Nathan - http://www.netdigix.com
Quoting Nathan lists@netdigix.com:
no its the prompt centos goes to when it cannot find anything to boot to.
So it's the grub prompt most likely. If it is, then your boot partition is either too large and part of it falls outside of BIOS addressable disk space (first 1024 cylinders), or is not positioned inside BIOS addressable disk space (basically, same thing). Grub can access disk drives only using BIOS calls. It needs to be able to access files in /boot/grub directory, as well as kernel and initrd images in /boot directory. All those files *must* be in BIOS addressable range, or booting will fail. Fdisk will issue a warning describing this for disks with more than 1024 cylinders. Unfortunately, you won't get such warning during graphical install. Grub isn't really verbose about this either (it just drops to CLI, without telling user where the problem is).
You can easily check if what I just described is the problem you are having. Boot from CD into rescue mode. Invoke fdisk and print out partition table. The start and end cylinder of partition that holds /boot directory must be bellow 1024. If they are not, you are in trouble.
If this is the problem you are having, the easiest way is to reinstall with above limitations in mind. Common way of dealing with this BIOS limitation is to create separate partition for /boot, and to make sure entire partition used for /boot is inside first 1024 cylinders. For example, by making /boot be first partition on the disk, and having it relatively small (100MB is more than enough for this partition). This is limitation of the BIOS, nothing to do with CentOS (any other operating system).
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Aleksandar Milivojevic -
Nathan -
Will McDonald