Tag Archives: redhat

Disable the filesystem check (fsck) at boot time

There’s several ways of accomplishing this. I will list all the methods beneath, just pick the one that fits the situation/you.

  • Filesystem tunable
  • Grub boot parameter
  • Placing command files on your root device
  • Active reboot without FSCK

Filesystem tunable

Use the tune2fs command to tell your filesystem to have a max count of mounts before a check to 0 to disable it.

# tune2fs -c 0 /dev/sda1

Parameter reference:

-c max-mount-counts
 Adjust the number of mounts after which the filesystem will be  checked  by  e2fsck(8).   If max-mount-counts  is  0  or -1, the number of times the filesystem is mounted will be disregarded by e2fsck(8) and the kernel.

Grub boot parameter

Add the following at the end of your grub boot linux line.

fastboot

This can be done by editing “grub.conf” or by editing the boot command via the grub menu at boot.

Placing command files on your root device

To disable the filesystem check on boot.

# touch /fastboot

To enable a filesystem check on boot.

# touch /forcefsck

Active reboot without FSCK

# shutdown -rf

Parameter reference:

-r     Reboot after shutdown.
-f     Skip fsck on reboot.

// CrashMAG

Linux ACL

An access control list (ACL), with respect to a computer file system, is a list of permissions attached to an object. ACL allows you to grant or deny permissions for any user or group on a filesystem resource.

Enabling ACL

To enable ACL, edit your /etc/fstab file as such:

/dev/VolGroup00/LogVol00 /                       ext3    defaults,acl        1 1

Note: Moderm Redhat distributions enable ACL by default for the root filesystem.

Set ACL

To modify ACL use setfacl command. To add permissions use setfacl -m.

Add permissions to some user:

# setfacl -m "u:username:permissions"

or

# setfacl -m "u:uid:permissions"

Add permissions to some group:

# setfacl -m "g:groupname:permissions"

or

# setfacl -m "g:gid:permissions"

Add default ACL:

# setfacl -d -m "u:uid:permissions"

Remove all permissions:

# setfacl -b

Remove each entry:

# setfacl -x "entry"

To check permissions use:

# getfacl filename

Examples

Set read,write and execute permissions for user “johndoe” on the file named “abc”.

# setfacl -m "u:johndoe:rwx" abc

Check permissions.

# getfacl abc
# file: abc
# owner: someone
# group: someone
user::rw-
user:johny:rwx
group::r--
mask::rwx
other::r--

Change permissions for user “johndoe”.

# setfacl -m "u:johndoe:rw-" abc

Check permissions.

# getfacl abc
# file: abc
# owner: someone
# group: someone
user::rw-
user:johndoe:rw-
group::r--
mask::r-x
other::r--

Remove all extended ACL entries.

# setfacl -b abc

Check permissions.

# getfacl abc
# file: abc
# owner: someone
# group: someone
user::rw-
group::r--
other::r--

Additional Resources

man getfacl
man setfacl

If you weren’t using these already, you should.

// CrashMAG