Re: [gentoo-user] Re: Need help: Filesystem (ext4) corrupted!

[Francisco Ares]

Em 03/09/2013 13:12, <meino.cramer@×××.de> escreveu:
>
> William Kenworthy <billk@×××××××××.au> [13-09-03 17:16]:
> > On 03/09/13 11:26, meino.cramer@×××.de wrote:
> > > William Kenworthy <billk@×××××××××.au> [13-09-03 05:08]:
> > >> On 03/09/13 10:45, meino.cramer@×××.de wrote:
> > >>> walt <w41ter@×××××.com> [13-09-03 04:15]:
> > >>>> On 09/02/2013 09:15 AM, meino.cramer@×××.de wrote:
> > >>>>> The rootfs and $HOME of my embedded system is stored
> > >>>>> on a 16GB SD-card (about 5GB used, rest free). The FS
> > >>>>> is ext4.
> > >>>>>
> > >>>>> Since the system hangs for unknown reasons several times
> > >>>> Does it hang at a predictable point, like during boot, or poweroff?
> > >>>>
> > >>>> I know almost nothing about SD cards (yet).  Do they develop bad
> > >>>> blocks like other storage media?  I notice fsck.ext4 has a -c flag
> > >>>> to check for bad blocks.
> > >>>>
> > >>> No, it hangs while compiling or while updateing (eix-sync; emerge
...).
> > >>>
> > >>>
> > >>> I did the following now:
> > >>> I did a binary image backup with dd of the sdcard.
> > >>> I made a backup of the all files from the bad fs with tar.
> > >>> I say "YES" to fsck to fix what it found.
> > >>> I made another backup of the all files from the bad fs with tar.
> > >>> I md5summed both tar archives and found them identical.
> > >>>
> > >>> Now...is the conclusion correct, that the identical md5sum
> > >>> indicate, that the fixed error of the fs only had impact to
> > >>> already invalidated data?
> > >>> Or whatelse could this indicate?
> > >>>
> > >>> Best regards,
> > >>> mcc
> > >>>
> > >>> PS: What come mind just in this moment:
> > >>> Can I ran fsck on an binary image of the fs which I made with dd
somehow?
> > >>>
> > >>>
> > >>>
> > >>>
> > >>>
> > >> Have you run out of inodes? - ext 4 has had very mixed success for
me on
> > >> solid state.  Running out of inodes is a real problem for gentoo on
> > >> smaller SD cards with standard settings.
> > >>
> > >> BillK
> > >>
> > >>
> > >>
> > > Does this error message from fsck indicate that? I am really bad in
> > > guessing what fsck tries to cry at me ... ;)
> > >
> > >
> > >>>     solfire:/root>fsck.ext4 -f -p /dev/sdb2
> > >>>     rootfs: Inodes that were part of a corrupted orphan linked list
found.
> > >>>
> > >>>     rootfs: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.
> > >>>         (i.e., without -a or -p options)
> > >>>     [1]    18644 exit 4     fsck.ext4 -f -p /dev/sdb2
> > >>>
> > >>>
> > > Is there any way to correct the settings from the default values to
> > > more advances ones, which respect the sdcard size of 16GB *without*
> > > blanking it...a "correction on the fly" so to say???
> > >
> > > And if not: Is there a way to backup the sdcard and playback the files
> > > after reformatting it by preserving all three time stamps of the
> > > files (atime is deactivated via fstab though) ?
> > >
> > > Best regards,
> > > mcc
> > >
> > >
> > >
> > >
> > >
> > df -i - if you get 100% iUSE or near to it thats your problem ... I have
> > seen that error message you give as a result of running out of inodes
> > corrupting the FS.
> >
> > No, your only way out is to copy (I use rync) the files off, recreate
> > the fs with max inodes ("man mke2fs") and rsync the files back.  Once an
> > ext* fs has been created with a certain number of inodes its fixed until
> > you re-format.
> >
> > I get it happening regularly on 4G cards when I forget and just emerge a
> > couple of packages without cleaning up in between packages.  On 16G
> > cards, its compiling something like glibc or gcc that uses huge numbers
> > of inodes at times.  On a single 32G card I have, the standard settings
> > have been fine ... so far :)
> >
> > Billk
> >
> >
>
> df -i gives the following:
>
> rootfs           971040 352208   618832   37% /
> /dev/root        971040 352208   618832   37% /
> devtmpfs          63420    434    62986    1% /dev
> tmpfs             63456    389    63067    1% /run
> shm               63456      1    63455    1% /dev/shm
> cgroup_root       63456      6    63450    1% /sys/fs/cgroup
> /dev/mmcblk0p1        0      0        0     - /boot
>
>
> You mentioned rsync to backup...
>
> I used
>
>     sudo tar cvf <backup file> <root of embedded system>
>
> the rootfs has only one partition...
>
> Is it alos ok to use tar or is there any drawback....?
>
> Best regards,
> mcc
>
>
>

There are some parameters for creating a better backup archive using tar,
like --same-owner and --atime- preserve.

By the way, it would be an interesting project to export some folders on
your home computer using nfs, tuneling it through ssh, monting it locally
in your embedded computer, and applying an unionfs to the rootfs.  Just
dreaming, of course.

Góod luck
Francisco