minus disk usage

Stephen Samuel samuel at bcgreen.com
Sat Feb 5 04:16:30 UTC 2011


Sooner or later, the system WILL come to a stop -- either on purpose, or in
a crash ... the only question is whether or not it will be recoverable.

Then again, how big is the filesystem? .. Nevermind... I looked back at your
original post.

A couple of ideas:
  1) make a backup AS SHORT AS POSSIBLE before shutting down the system...
If possible, after all services have been shut down.
(if you can't do that, then backup everything, then backup everything that's
changed since the first backup started, then  shut  down services and
backup everything since the incremental backup started.  (for minimal down
time).

If you've backed up to a second system that can replace the running (and
broken system), then use the second system in place of the corrupt system,
and you're now relatively happy.  You can work on cleaning up the filesystem
and/or figuring out what broke it.
otherwise, you can either (1) wipe the filesystem and restore it from
backup, or (2) FSCK the system in hopes of cleaning things up ((( or,
ultimately, both, if #2 fails))).

A couple of more options:
1: install / build smartmontools for your system and make sure that the
drive, itself, isn't failing.
2: the problem is with your root filesystem, and I'm presuming that /home is
where most of your 'live' data is.  This means that, if you follow the
process above, your final incremental backup should be TINY.
    If the hard drive, itself, isn't failing, then you can build yourself a
new root filesystem  (on an external usb/esata drive, if you don't
have hot-swap capability) from/as your backup , and boot off of that.  That
would mean a minimal investment in new hardware (if you have a limited
budget
and/or esoteric hardware on your system). and minimal downtime (a few
minutes) .
If you have a second machine with the same/similar mother board, then you
can practice booting off of the spare drive there.

Worst case would be to boot off of a live CD and do an FSCK that way, but it
could take quite a while, and there is no guarantee that the filesystem will
have all of the parts left to be bootable after that, if FSCK removes a
bunch of critical files -- or the files are already corrupted.


On Fri, Feb 4, 2011 at 9:04 AM, Uematsu Takeshi
<takeshi.uematsu at gmail.com>wrote:

> Stephen,
> Thank you for your adviece.
>
> I have not done an FSCK yet.
> /dev/sda2 is /(root) partition.
> I know that it shouldn't execute fsck with the mounted filesystem.
> and cannot umount root file system.
>
> This system cannot be stopped.
> Do you know how to check the filesystem without stop ?
>
>
> 2011/2/4 Stephen Samuel <samuel at bcgreen.com>:
> > 1) do a backup (NOW!) if you haven't already done TWO.
> > 2) Have you done an FSCK with the filesystem unmounted?
> >       (given that you pretty clearly have some corruption, you might want
> to
> > do an 'fsck -n', and just see what FSCK is proposing to do to the system.
> >
> > On Thu, Feb 3, 2011 at 7:57 PM, Uematsu Takeshi <
> takeshi.uematsu at gmail.com>
> > wrote:
> >>
> >> Hi,This is Takeshi Uematsu.
> >>
> >> I have a trouble on the ext3 filesystem.
> >> The df command indicates minus disk usage.
> >> Dose anyone know why this happned ?
> >> Any ideas be appreciated.
> >>
> >> # df -h
> >> Filesystem            Size  Used Avail Use% Mounted on
> >> /dev/sda2              97G  -26G  118G   -  /
> >> /dev/sda1              99M   15M   80M  16% /boot
> >> tmpfs                 2.0G     0  2.0G   0% /dev/shm
> >> /dev/sda3             803G  3.9G  758G   1% /home
> >>
> >> fdisk /dev/sda
> >>
> >>   Device Boot      Start         End      Blocks   Id  System
> >> /dev/sda1   *           1          13      104391   83  Linux
> >> /dev/sda2              14       13067   104856255   83  Linux
> >> /dev/sda3           13068      121193   868522095   83  Linux
> >> /dev/sda4          121194      121454     2096482+  82  Linux swap /
> >> Solaris
> >>
> >> _______________________________________________
> >> Ext3-users mailing list
> >> Ext3-users at redhat.com
> >> https://www.redhat.com/mailman/listinfo/ext3-users
> >
> >
> >
> > --
> > Stephen Samuel http://www.bcgreen.com  Software, like love,
> > 778-861-7641                              grows when you give it away
> >
>



-- 
Stephen Samuel http://www.bcgreen.com  Software, like love,
778-861-7641                              grows when you give it away
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