Linux: Skip or Bypass a Fsck

by on December 20, 2008 · 14 comments· LAST UPDATED December 20, 2008

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Q. I know how to force fsck on the next reboot using /forcefsck file. But how do I skip or bypass a fsck on reboot? How to stop a FSCK from prompting or running automatically when rebooting server.

A. It is recommended that you run a fsck on reboot if required. Usually, system automatically determines if fsck required or not. Generally, fsck is run automatically at boot time when the system detects that a file system is in an inconsistent state, indicating a non-graceful shutdown, such as a crash or power loss.

Bypass a fsck using shutdown command

When rebooting the server use the following command
# shutdown -rf now
Above command will reboot the system and will not run auto fsck.

Set Linux kernel option by editing grub.conf / menu.lst

Open grub.conf or menu.lst (usually located in /boot),
# vi /boot/grub.conf
Find kernel line and put fastboot at the end of the kernel line. In the end it should look as follow:
kernel /vmlinuz-2.6.18-92.1.22.el5 ro root=LABEL=/ console=tty0 console=ttyS1,19200n8 fastboot

Skip fsck by updating /etc/fstab file

Finally, you can edit /etc/fstab file which, contains descriptive information about the various file systems. You will see two numbers at the end of the line for each partition, change the second number to a 0 (zero digit). This will have the system mount the partition but will not run a check when booting. The sixth field, is used by the fsck program to determine the order in which filesystem checks are done at reboot time. The root filesystem should be specified with a fs_passno of 1, and other filesystems should have a fs_passno of 2. Filesystems within a drive will be checked sequentially, but filesystems on different drives will be checked at the same time to utilize parallelism available in the hardware. If the sixth field is not present or zero, a value of zero is returned and fsck will assume that the filesystem does not need to be checked. Here is sample entry:

LABEL=/disk3		/disk3			ext3	defaults	0 0
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{ 14 comments… read them below or add one }

1 MT December 21, 2008 at 8:13 am

Hi,

We can permanently bypass fsck check on any filesystem using tune2fs command as follows:

root@server[~]# tune2fs -i 0 /dev/sdb1
tune2fs 1.35 (28-Feb-2004)
Setting interval between check 0 seconds
root@server [~]#

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2 Dave K January 6, 2009 at 5:12 pm

Bizarre. I tried all of these tricks, and none of them worked.

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3 alkisg January 8, 2009 at 8:25 am

Is the kernel parameter method (with grub/menu.lst) really valid?

fastboot and forcefsck are not listed as valid kernel parameters,
and I don’t know if it’s an ubuntu-ism, but neither my /etc/rcS.d/S20checkroot.sh nor my /etc/rcS.d/S30checkfs.sh include support these parameters.

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4 chika.tambun April 24, 2009 at 1:26 pm

on my /etc/fstb
#
line 1: proc /proc proc defaults 0 0
line 2: /dev/sda1 / ext3 defaults,errors=remount-ro 0 1

just change
line 2: /dev/sda1 / ext3 defaults,errors=remount-ro 0 0

it will pass checking the root partition

it works for me

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5 Ralph September 25, 2009 at 8:09 pm

This was helpful information, but I’m still stuck … the machine is shut down, and on boot fsck auto-runs and exits into a maintenance shell telling me to run it manually. In that process it also mounts the file system as read-only. When I attempt to run fsck manually it hangs and all I see is a black screen.

1) can’t use the shutdown switch, since the machine is already off
2) tried to modify the boot options in grub, but fastboot doesn’t do anything
3) tried to modify fstab but it’s read only. Once I unmount the system (/dev/sda1), the device name no longer exists and I can’t mount it again as r/w

How do I prevent fsck for running at boot time and mounting the fs as ro? This is on xubuntu (hardy) … oOr alternatively, how do I remount the fs as rw in the maintenance shell …. Help ….?

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6 none November 23, 2010 at 6:48 pm

I believe you can remount read/write (instead of read only) like this:

mount -o remount rw /

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7 sam January 13, 2010 at 4:19 pm

How to do it on Debian:

touch /fastboot

Seen in /etc/init.d/checkfs.sh

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8 Sam Kear February 17, 2011 at 2:02 pm

Thanks this was just what I was looking for! I had a system that was stuck in a loop trying to fsck a bad hard drive. The fastboot option skipped the check and let me boot into the system to do what I needed.

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9 Chaitanya June 12, 2011 at 5:47 am

that was excellent option, solved a big problem of mine tq very much

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10 William December 9, 2011 at 3:01 pm

The first answer is so typical answer by linux people: never answering to the question and instead assuming the user is stupid. I I want to destroy my hard drive it’s up to me, no?

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11 Dane December 16, 2011 at 12:44 am

Is there a way to disable timed checks but ensures all disks are checked after a critical failure? Fedora, force checks after a certain amount of days and/or remounts.

However I would prefer to just reserve these checks if there is a valid reason for doing them.

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12 Alan K December 16, 2011 at 3:38 pm

I would really like to do the FSCK but not manually. Is there an option to have it run through it automatically without dropping to a command line during boot?

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13 Sam Watkins March 9, 2012 at 5:04 am

I decided to leave the auto-fsck in there, but write a program that warns me, when an auto-fsck is coming soon. Then I will have the opportunity to avoid it by running a manual fsck, e.g. before I turn off the computer at night.

The script needs to run as root, so it can read the device info with tune2fs -l

http://sam.nipl.net/code/nipl-tools/bin/fsck-convenient

Running this from .profile or on X startup without output to xmessage isn’t too hard.

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14 Lince Toddle May 3, 2012 at 5:38 pm

Thanks for your hints – last question is quite interesting,
well, in my case displaying an non-interactive splash screen
that tells the user just to stand by could be a neat one.

Also, periodical fscks could be run during shutdown instead?

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