HOWTO: Multi Disk System Tuning: Troubleshooting

Next Previous Contents

## 15. Troubleshooting

Much can go wrong and this is the start of a growing list of symptoms, problems and solutions:

## 15.1 During Installation

### Locating Disks

Symptoms

  Cannot find disk

Problem

  How to find what drive letter corresponds to what disk/partition

Solution

  Remember Linux does not use drive letters but device names. More information can be found in Drive names.

Symptoms

  Cannot partition disk

Problem

  Most likely wrong input to the command line for `fdisk` or similar tool.

Solution

  Remember to use `/dev/hda` rather than just `hda`. Also do not use numbers behind `hda`, those indicate partitions.

### Formatting

Symptoms

  Cannot format disk.

Problem

  Strictly speaking you format partitions not disks.

Solution

  Make sure you add the partition number after the device name of the disk, for instance `/dev/hda1` to the command line.

## 15.2 During Booting

### Booting fails

Symptoms

  Number keep scrolling up the screen.

Problem

  Possibly corrupt disk.

Solution

  Try another disk, you might have to reinstall. Check for loose cables and possible data corruption.

Symptoms

  Get `LI` and then it hangs.

Problem

  You use LILO to load Linux but LILO cannot find your root.

Solution

  Read the LILO HOWTO.

Symptoms

  Kernel panics, something about missing root file system.

Problem

  The kernel does not know where the root partition is.

Solution

  Use `rdev` or (if applicable) LILO to add information to the kernel image where your root is.

### Getting into Single User Mode

Symptoms

  System boots but get into a root shell in single user mode.

Problem

  Something went wrong in the later stages of booting and the system has come far enough to let you open a shell to repair the system.

Solution

  Locate the problems from the boot log. Note that file system can be in read-only mode. Remount read-write if you have to. Often the reason is that the `/etc/fstab` contained an entry that was mismapped such as trying to mount a swap partition as your normal file space.

## 15.3 During Running

### Swap

Symptoms

  Short on memory

Problem

  Swap space is not available

Solution

  Type free and check the output. If you get

  > `

  >                  total       used       free     shared    buffers     cached
  >     Mem:         46920      30136      16784       7480      11788       5764
  >     -/+ buffers/cache:      12584      34336
  >     Swap:       128484       9176     119308

  > `

  then system is running normal. If the line with `Swap:` contains zeros you have either not mounted the swap space (partition or swap file) (see `swapon(8)`) or not formatted the swap space (see `mkswap(8)`).

### Partitions

Symptoms

  No room amidst plenty 1

Problem

  Partitionitis:Underdimensioned partition sizes has caused overflow in some areas

Solution

  Examine your partition usage using `df(1)` and locate problem areas. Normally the problem can be solved by removing old junk but you might have to repartition your system, see section Repartitioning.

Symptoms

  No room amidst plenty 2

Problem

  Running out of i-nodes has caused overflow in some ares, often in areas with many small files such as news spool.

Solution

  Examine your partition usage using `df -i` and locate problem areas. Normally the problem is solved by reformatting using a higher number of i-nodes, see `mkfs(8)` and related man pages.

Next Previous Contents