Re: BUG EXT3-fs: fragsize 1024 != blocksize 4096 (unsupported)

[Jan Kara <jack@suse.cz>]

On Tue 06-04-10 21:35:09, Oscar Megia wrote:
> Yes, it was a problem with the ATX power supply. I replaced it and now
> is working fine.
> 
> I did what you told and I recover my important data but not all fs.
> 
> The matter is if you have a hardware fault the ext3 journal fs don't
> preserve your data.
> 
> I'm not an expert about the journal ext3 fs but I though is designed
> to preserve data so if the HD has a fault, ext3 must preserve your
> data. If the fault is during updating the main fs it must go to the
> previous main fs. This could happen when there is a power cut.
  Ext3 journal prevents filesystem corruption only in case the power
fails suddently. Also cases like kernel crashes are usually solved by the
journal quite fine. But in situations like flaky power supply where memory
can provide wrong data to disk or disk writes only some data because of
weak voltage, journaling does not help at all. Generally, only good backups
are a solution to bugs in HW...

									Honza
> 2010/3/17 Jan Kara <jack@suse.cz>:
> >  Hi,
> >
> > On Tue 16-03-10 13:05:09, Oscar Megia wrote:
> >> Since three days ago mi PC with Fedora 9 started to do random resets.
> >>
> >> I started to change the BIOS configuration and one of this changes leaved
> >> the screen black. Unfortunately, I pressed the reset button thinking that
> >> didn't boot but the next time (after leave the BIOS configuration like
> >> before) the system didn't boot.
> >  I'd check your HW - memory, power supply, ... Obviously something got
> > wrong.
> >
> >> It showed me this message: "EXT3-fs: fragsize 1024 != blocksize 4096
> >> (unsupported)" (you can see two pictures booting with this error at
> >> http://forums.fedoraforum.org/attachment.php?attachmentid=19240&d=1268739264
> >> and http://forums.fedoraforum.org/attachment.php?attachmentid=19239&d=1268739254).
> >>
> >> Researching I could get info from the root fs with dumpe2fs:
> > ...
> >>
> >> hda1 is for boot and hda2/lvm/ext3 with the OS and  data. If the ext3
> >> has journal, is this a bug in the ext3 journal filesystem?
> >  I'd say it is a faulty HW, not a software bug.
> >
> >> My question is how can repair this lvm/ext3 volume without loose data?
> >  I would first try to identify faulty HW (run memtest from a rescue CD
> > for example). When HW gets fixed, I'd copy the filesystem with 'dd' to a
> > different disk as a backup. Then run e2fsck to fix /dev/hda2.
> >
> >                                                                Honza
> > --
> > Jan Kara <jack@suse.cz>
> > SUSE Labs, CR
> >
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR
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