Ubuntu 12.04 on Amazon EC2: /dev/xvda1 will be checked for errors at next reboot?
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I'm running the lastest Ubuntu 12.04 AMI (ami-a29943cb) from Canonical on Amazon EC2 and quite often when I log in I get the message:
*** /dev/xvda1 will be checked for errors at next reboot ***
I have read a bunch of documentation on this and seem to understand that every so many reboots (around 37 see Mount count / Maximum mount count below) Ubuntu wants to check a disk for errors. I can see that by using dumpe2fs -h /dev/xvda1 (reference) to get information such as:
Last mounted on: /
Filesystem UUID: 1ad27d06-4ecf-493d-bb19-4710c3caf924
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: 524288
Block count: 2097152
Reserved block count: 104857
Free blocks: 1778055
Free inodes: 482659
First block: 0
Block size: 4096
Fragment size: 4096
Reserved GDT blocks: 511
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 8192
Inode blocks per group: 512
Flex block group size: 16
Filesystem created: Tue Apr 24 03:07:48 2012
Last mount time: Thu Nov 8 03:17:58 2012
Last write time: Tue Apr 24 03:08:52 2012
Mount count: 3
Maximum mount count: 37
Last checked: Tue Apr 24 03:07:48 2012
Check interval: 15552000 (6 months)
Next check after: Sun Oct 21 03:07:48 2012
Lifetime writes: 2454 MB
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
Default directory hash: half_md4
Directory Hash Seed: 0a25e04c-6169-4d68-bfa6-a1acd8e39632
Journal backup: inode blocks
Journal features: journal_incompat_revoke
Journal size: 128M
Journal length: 32768
Journal sequence: 0x0000158b
Journal start: 1
I've tried these things to get rid of the message and usually the badblocks is what does it for me:
Run this command and reboot:
sudo touch /forcefsck
Run badblocks to check the disk:
badblocks /dev/sda1
Edit /etc/fstab and change the last "0" which is the fs_passno column accordingly and then reboot:
The root filesystem should be specified with a fs_passno of 1, and other filesystems should have a fs_passno of 2.
I don't understand:
If this is a virtual drive shouldn't it be less prone to errors?
Was the image created with one of the flags set? If not what is triggering it?
Why is fs_passno set to 0 on Amazon EC2 Ubuntu images? This is not the first one that is like this.