Why is my root filesystem always scanned at boot?

Question

I always have a pause at boot saying my filesystems are being checked (with a "press C to cancel" note, too). Actually (seeing boot.log) I think it's the / fs, which is located at /dev/sdb5

Several questions altoghether, here (hope this does not break any rule):

• Is this normal?
• Can I (or even should I) prevent this anyhow?
• According to boot.log (below) the fs does not seem to be 'clean', or, at least, it's in an state or condition that makes fsck always can it for errors for a while (just a few seconds). How can I fix it?

Edit: This is my boot.log:

fsck desde util-linux-ng 2.17.2
udevd[515]: can not read '/etc/udev/rules.d/z80_user.rules'


/dev/sdb5: 249045/32841728 ficheros (0.3% no contiguos), 20488485/131338752 bloques
init: ureadahead-other main process (1111) terminated with status 4

init: ureadahead-other main process (1116) terminated with status 4

Password:  * Starting AppArmor profiles       [160G Skipping profile in /etc/apparmor.d/disable: usr.bin.firefox

[154G[ OK ]
 * Setting sensors limits       [160G 
[154G[ OK ]

And this is dumpe2fs results for the filesystem being checked (well, the relevant part of the log):

Filesystem volume name:   <none>
Last mounted on:          /
Filesystem UUID:          42509bf9-f3e6-460a-8947-ec0f5c1fbcc8
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              32841728
Block count:              131338752
Reserved block count:     6566937
Free blocks:              110850356
Free inodes:              32592701
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      992
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Fri Dec 10 19:44:15 2010
Last mount time:          Mon Feb 14 17:00:02 2011
Last write time:          Mon Feb 14 16:59:45 2011
Mount count:              1
Maximum mount count:      33
Last checked:             Mon Feb 14 16:59:45 2011
Check interval:           15552000 (6 months)
Next check after:         Sat Aug 13 17:59:45 2011
Lifetime writes:          331 GB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:           256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
First orphan inode:       28049496
Default directory hash:   half_md4
Directory Hash Seed:      d3d24459-514b-4413-b840-e970b766095b
Journal backup:           inode blocks
Journal features:         journal_incompat_revoke
Tamaño de fichero de transacciones:  128M
Journal length:           32768
Journal sequence:         0x0005e0c4
Journal start:            1

This is my /etc/fstab file:

# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>

proc    /proc   proc    nodev,noexec,nosuid 0   0

#Entry for /dev/sdb5 :
UUID=42509bf9-f3e6-460a-8947-ec0f5c1fbcc8   /   ext4    errors=remount-ro   0   1

#Entry for /dev/sdb1 :
UUID=685EC6355EC5FC36   /media/DATOS    ntfs    defaults,user   0   0


#Entry for /dev/sda2 :
UUID=6A366B05366AD21D   /media/W7   ntfs    defaults,nosuid,nodev,uhelper=udisks,uid=1000,gid=1000,dmask=0077,fmask=0177    0   0

#Entry for /dev/sdb6 :
UUID=66aa7f93-4c89-4118-af47-fdaa78db8f22   none    swap    sw  0   0

#Lector de tarjetas impresora
//192.168.85.77/Memory_Card /media/HP smbfs defaults 0 0

Solution 1

All looks OK in the outputs... :P

Two more things you can try:

1. check if a /forcefsck file exists on your system;
2. boot into a LiveCD and force the check of the partition, for example using GParted → Partition → Check.

Solution 2

Maybe you don't let it finish. It is a scheduled process every 30 boots. The linux file-system is checked. You can start this process by: shutdown -rF now This will restart and start the check.

Edit the check by running: gksu gedit /etc/fstab Last digit of every mounting line controls the fsck. Set value to 0 if want to disable fsck. for example: /dev/hda1 /media/window_c vfat defaults 0 0

Comments

[samme4life]

Can you please check the output of dumpe2fs (especially the filesystem state field) when the partition is UNMOUNTED? You can e.g. restart the computer and boot into a LiveCD and check the output from there.

[luri]

When booted from LiveCD Filesystem state says clean (same as in log above). Boot pauses about 20 seconds to check filesystems... it's just a bit annoying. I added relevant fstab line to question.

[samme4life]

Could you post the whole /etc/fstab file? Also: do you access the ext4 partitions from Windows or other OS?

[luri]

Not usually I think once or twice I did some weeks ago, but just to read a file. I'll update the question with whole /etc/fstab now.

[luri]

No /forcefck I can find, and I already ckecked the partition (from Disk utility and with fsck when booted from a LiveCD)

[luri]

I also chkdsk'ed the two NTFS partitions in W7, just to be sure. A few errors were corrected in one of them, but still I got the filesystem check when booting. Even though I'd say it's sdb5 which is being checked, (dumpe2fs Mount count is always 1, unless I skip the check -pressing c-), is there any way to check if the rest of filesystems are 'clean' (as dumpe2fs won't work on them, afaik)?

[luri]

Stupid me!! I checked for /forcefsk in the wrong console (the one in my laptop instead of the one I had ssh'ed into my desktop).... So the answer is YES, there is a /forcefsk file. Can you post an answer so that I can mark it as "Accepted"?

[luri]

I always let it finish (does not take long, tho). I have this line in fstab: UUID=42509bf9-f3e6-460a-8947-ec0f5c1fbcc8 / ext4 errors=remo‌​unt-ro 0 1 So if I have understtod you correctly, this line is making ubuntu fsck my / at every boot. Should I change last digit to 0, or should I leave it as is? I mean... is it -by default- supposed to check / at everyboot or is it a misconfiguration of my fstab file?

[LGB]

I think the check is scheduled by these conditions: no clean umount, max mount count is reached or max time interval elapsed since the last fsck. dumpe2fs can tell you those settings (it's better to redirect to the file, and check it later, since it dumps large amount of information). If the interval/mount count is not your case, then it can be the unclean shutdown. Maybe your filesystem cannot be unmounted cleanly on shutdown/reboot that's why it's checked then. I am not sure it helps but maybe /var/log/boot.log tells the reason or you can read on boot ("unclean" or something?).

[LGB]

Btw, I wouldn't recommend to set the last field in fstab to zero, it will surely solve your problem but then there is no fsck even if it's really needed, and it can be sometimes dangerous to use a non-fsck'ed fileystem which would be the case if there is no fsck at all on startup even if it is really needed.

[luri]

I added dumpe2fs resuts for sdb5 (the fs being checked always at boot), in case that helps.... But my question is... should that entry be 1 by default? Should it (again I mean by default) be set to 0 or to 30 or...? In other words... is it really normal that it is fsck'ed at each boot? I don't want to disable fsck on it (although it is set to 0 in all the other filesystems), just make it run when necessary.

[luri]

Added boot.log... Doesn't say it's clean, but doesn't say it's unclean, either. It says: "/dev/sdb5: 249648/32841728 ficheros (0.3% no contiguos), 20503149/131338752 bloques". I don't really understand why it's checked EVERY boot.... The 6th parameter in fstab is also set to 1 in another computer's root fs (same Ubuntu version) and it's not checked EVERY boot. Can I fsck / with some parameter to do kind of full check?

[luri]

As I said before, the /forcefsk file was the problem. File is gone, problem is gone.