Ubuntu forces drives to be checked once for every 30 times the filesystem is mounted. This means that on an average, once every 30 times you bootup your computer, the filesystem integrity is checked. This is very reasonable for a desktop, which is seldom rebooted. However, for a laptop, this means pain, since you may be planning on making a presentation, and Ubuntu may start a filesystem check just when you hook up your laptop to the projector and bootup! Today we will see how to disable (or force) the checking temporarily, and also how to adjust the period and frequency of the check.

To disable filesystem integrity check for the next bootup, create a file called /fastboot. So a
$sudo touch /fastboot
will disable filesystem check for the next time you bootup. Since the /fastboot file is removed during bootup, this will disable filesystem check only once - for the one time you bootup after you create the /fastboot file (which need not have anything in it — hence the touch, which only creates the file)
On the contrary to force a filesystem check the next time you bootup, create a file called /forcefsck by doing
$sudo touch forcefsck

Now, on to the more interesting business of how to change the number of bootups between filesystem checks, and modifying the period with which the filesystem is checked. The following applies to ext2 and ext3 filesystems.

tune2fs is an utility that you can use to change both the number of bootups between filesystem checks, and the number of days/weeks/months between filesystem checks.

For example to have the filesystem checked once every 60 bootups use
$sudo tune2fs -c 60

To have the filesystem check run periodically, say once a week, use
$sudo tune2fs -i 1w
changing the “w” to “d” or “m” will have the check run once daily and once monthly - you get the idea.

As always, you can read
$man tune2fs
for more detailed information and examples.