dump on ext3

dump on ext3

[Kirkwood, David A]

Does dump work reliably on an ext3 filesystem?

Here's the senario:

I have a raid 5 linux system ( RH 7.3 ). I currently backup the system to
tape in case of catastrophic failure. I am up to multitape backups for full
user partitions.I want to use incremental dumps and spread my full system
dumps further apart, but tme man page says dump can be used for ext2. There
is no mention of ext3 one way or the other. Assuming 1 tape drive, the need
to do backups unattended, the inability to shut the system down  
everttime I need to dump files, I need to use dump unless someone has a
better solution. New backup h/w etc in not an option as i have already
submitted need for tape library etc and its working its way through the
corporate higharchy but it may be 6 month untill I see something.

As always, all input is appreciated.

Dave

Re: dump on ext3

[Jim C. Brown]

On Thu, Jan 06, 2005 at 04:13:16PM -0500, Kirkwood, David A wrote:
> Does dump work reliably on an ext3 filesystem?
> 
> Here's the senario:
> 
> I have a raid 5 linux system ( RH 7.3 ). I currently backup the system to
> tape in case of catastrophic failure. I am up to multitape backups for full
> user partitions.I want to use incremental dumps and spread my full system
> dumps further apart, but tme man page says dump can be used for ext2. There
> is no mention of ext3 one way or the other. Assuming 1 tape drive, the need
> to do backups unattended, the inability to shut the system down  
> everttime I need to dump files, I need to use dump unless someone has a
> better solution. New backup h/w etc in not an option as i have already
> submitted need for tape library etc and its working its way through the
> corporate higharchy but it may be 6 month untill I see something.
> 
> As always, all input is appreciated.
> 
> Dave

I'm not 100% certain of this, but it should work. File system wise, ext3
is just ext2 with a journal inode (which looks like a regular ext2 file).

I suppose it is possible that dump might have a problem with the journal inode
on a mounted ext3 system, but even if that is the case it should be easy to work
around, as it seems Dump 0.4b36 from http://sourceforge.net/projects/dump/
supports ext3 (all versions do, but that's the only one called ext2/ext3 dump).

You might also be interested to read this, from
http://nslug.ns.ca/pipermail/nslug/2003-November/005980.html

> Changes between versions 0.4b9 and 0.4b10 (released November 21, 1999)
> ======================================================================
> ...
> 4.      Integrate a patch from Jeremy Fitzhardinge <jeremy at goop.org>
>         which allows dump on an active ext3 filesystem. However, this
>         is a "quick and dirty" patch which enables backup of an ext3
>         filesystem through the ext2 compatibility (by ignoring the
>         NEEDS_RECOVERY bit). The journal file is not recognized and
>         it is dumped (it should not).
>
>
> Unless I have missed something, nobody ever saw a need to improve on the
> "quick and dirty" patch (or at least there is no subsequent mention of ext3
> in the changelog) so it should be possible with a modern 'dump' to dump ext3
> and get exactly the same results as if the filesystem had been ext2, just as
> it says above.
>

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.