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Enable or disable boot time services in SUSE

Ryan — Fri, 14 Jan 2011 18:08:03 +0000

There are a couple ways to enable or disable system services at boot time in SUSE.

From the command line:

To enable a service:
$ sudo insserv SERVICE

To disable a service from starting:
$ sudo insserv -r SERVICE

You can also use YaST:

YaST Control Center -> System -> System Services (runlevel)

Select the service you want to change then click either the Enable or Disable button.

Install the GRUB boot loader to the MBR

Ryan — Sat, 29 Nov 2008 02:58:03 +0000

You might need to reinstall the boot loader to the master boot record (MBR) if it becomes corrupted or erased. This can occur for example if Windows is installed on another partition which overwrites the MBR.

There are two ways to reinstall grub, automatically using grub-install, and manually through grub itself. grub-install is a script which calls grub underneath and in most cases it is your best solution. Sometimes the manual approach is better if you have a complex setup or the first option fails.

The GRUB naming scheme for hard drives and partitions is a bit confusing at first. Hard drive and partition numbers are ordererd with the count starting at zero. They are ordered based on the boot sequence in BIOS, so different types (IDE, SCSI, or RAID) my be intermixed.

For example a system with 2 PATA disks and 1 SATA disk might have the following drive mapping.
/dev/hda = (hd0) = drive 1
/dev/hda1 = (hd0,0) = drive 1, partition 1
/dev/hdb2 = (hd1,1) = drive 2, partition 2
/dev/sda1 = (hd2,0) = drive 3, partition 1

These steps require root privileges so switch to root or use sudo.

Install automatically with grub-install. The first argument is the hard drive where the boot loader will installed onto the MBR. It will use your current root directory partition for the rest of the installation. Change “/dev/sda” to the correct device for your system.

# grub-install /dev/sda

If you have a separate boot partition use the –root-directory option to install GRUB on that device instead of your root partition.

# grub-install --root-directory=/boot /dev/sda

The second method will allow you to install the boot loader manually with grub. Start by launching the GRUB command shell.

# grub

If your not sure of the device to specify for the installation, you can ask GRUB to tell you. Run this command and GRUB will attempt to find your GRUB installation on all available device partitions on the system. If found GRUB will output all the partitions containing GRUB installations in GRUB naming format. You can select the correct device and use in the next step.

grub> find /boot/grub/menu.lst

 (hd0,0)

Set your root partition which contains the boot directory as well as the GRUB installation. You can use the output from the step above.

grub> root (hd0,0)

Install GRUB to the MBR of your first hard drive device.

grub> setup (hd0)

Exit Grub.

grub> quit

Reboot, you should hopefully see the menu on start up.

# reboot

Run a command at boot with Gentoo

Ryan — Mon, 27 Oct 2008 12:41:33 +0000

Normally in Gentoo you would want to create an init script via rc-update to start a service at boot. However if there are a few miscellaneous commands you would like to run you can add them to local.start.

The local.start init script is similar to rc.local in other distributions. It is the last init script to be run after all other services have been started at the end of the boot process.

Add your commands to local.start file located here.
/etc/conf.d/local.start

You can also make commands run when the system is shutdown. These commands should be placed in local.stop located here.
/etc/conf.d/local.stop

Disable ext3 boot-time check with tune2fs

Ryan — Sun, 26 Oct 2008 19:09:18 +0000

The ext3 file system forces an fsck once it has been mounted a certain number of times. By default this maximum mount count is usually set between 20-30. On many systems such as laptops which can be rebooted quite often this can quickly become a problem. To turn off this checking you can use the tune2fs command.

The tune2fs command utility operates exclusively on ext2/ext3 file systems.

To run these commands you must run the command as root or use sudo. You must also make sure that your filesystem is unmounted before making any changes. If you are doing this on your root partition the best solution is to use a LiveCD.

You can run tune2fs on the ext3 partition with the ‘-l‘ option to view what your current and maximum mount count is set to currently.

tune2fs -l /dev/sda1

...
Mount count:              2
Maximum mount count:      25
...

To turn off this check set the maximum count to 0 with the ‘-c‘ option.

# tune2fs -c 0 /dev/sda1

If you do not want to completely disable the file system checking, you can also increase the maximum count.

# tune2fs -c 100 /dev/sda1