Difference between revisions of "Troubleshooting"

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[[File:kernel_panic.png|thumb|none|400px|Kernel panic - no syncing]]
 
[[File:kernel_panic.png|thumb|none|400px|Kernel panic - no syncing]]
 
=== My kernel won't boot! How do I rebuild it? ===
 
 
If you broke your kernel and can no longer reboot, either by removing a necessary feature for booting or maybe making it a [M] module instead of [*] built-in, you will need to re-enter your installed environment by using the original CRUX installation iso ([[Troubleshooting#My_kernel_won.27t_boot.21_How_do_I_rebuild_it.3F|rescue procedure]]).
 
# Remount your CRUX Linux iso
 
# Reboot your system and boot from the ISO
 
# Type in <tt>CRUX</tt> and press <tt>enter</tt>
 
# Log in as <tt>root</tt>
 
# Type in the following commands:
 
<nowiki>
 
# mount /dev/sda1 /mnt
 
# setup-chroot
 
# cd /usr/src/linux-2.6.25.6
 
# make menuconfig
 
# make all
 
# make modules_install
 
# cp arch/x86/boot/bzImage /boot/vmlinuz
 
# cp System.map /boot/
 
# lilo
 
# shutdown now
 
</nowiki>
 
Finally, unmount the iso and reboot the system.
 
  
 
=== "error: couldn't mount because of unsupported optional features (240/244)" ===
 
=== "error: couldn't mount because of unsupported optional features (240/244)" ===

Revision as of 23:06, 16 June 2011

Installation issues

Boot issues

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,1)

This issue can arise from one of two reasons:

  1. The boot partition's filesystem was not built into the kernel (e.g., EXT4/ReiserFS)
  2. The kernel does not have the appropriate SATA/hard disk controller drivers in order to recognize the boot partition
Kernel panic - no syncing

"error: couldn't mount because of unsupported optional features (240/244)"

This is more of a warning than an error. It occurs because the boot sequence attempts to read the boot partition with EXT3/EXT2, which is not the actual filesystem. It then continues by attempting ReiserFS/EXT4 and successfully locates the kernel. Since it gives the impression of an unclean installation, you can suppress these errors most easily by removing EXT3/EXT2 support in the kernel--neither filesystems will be used in MineOS. Otherwise, you can simply ignore it.

error: couldn't mount

"FATAL: No bootable medium found! System halted."

Depending on what steps you have completed, this can mean different things.

  • If are starting from the very, very beginning, it simply means the CRUX Linux iso is not mounted
  • If you have already compiled and copied the kernel as /boot/vmlinuz, check two places:
    • After copying vmlinuz and System.map to /boot, did you run lilo?
      • Running lilo should report no errors.
    • In fdisk</t>, type p <enter> to see the master boot record. Is partition one marked with an asterisk (*) as bootable?
      • If not, mark it as bootable with:
a <enter>
1 <enter>
p <enter> (verify bootable flag set)
w <enter>

Ports issues

Scripts issues

Connectivity issues

"Network error: Connection timed out" -- cannot SSH

SSH connection timed out

This can be caused for numerous reasons.

  1. Server is currently down
  2. attempting to connect to incorrect IP address
  3. Network routing not set up
  4. SSH server not enabled/inbound connections not allowed
  5. sshd (SSH background daemon process) not running
  6. iptables (firewall) prohibiting connection