On Monday 22 October 2007 12:36:32 Soeren Sonnenburg wrote:
quoted text
> On Mon, 2007-10-22 at 11:48 +0200, Bernd Schubert wrote:
> > Hello,
> >
> > On Monday 22 October 2007 04:12:44 Tejun Heo wrote:
> > > Helo,
> > > [...]
> > >
> > > > Now when I write large files of zeros to root(sda&sdb) and read the
> > > > file back in it contains a few nonzero entries:
> > > >
> > > > # dd if=/dev/zero of=/foo bs=1M count=2000
> > > > # hexdump /foo
> > > > 0000000 0000 0000 0000 0000 0000 0000 0000 0000
> > > > *
> > > > <after >1GB random parts, within large blocks of zeroes>
> > > >
> > > > I can reliably trigger this on the md0 / devmapper-root setup when I
> > > > write about 2GB of data (note that this machine has 1.5G of memory -
> > > > and still 1GB is often enough to see this problem). Here it does not
> > > > matter where in the filesystem I do these writes.
> >
> > Thats almost the same test as I'm always doing. Only I do not write only
> > 2GB,
>
> Well when I read your mail I thought that I could be seeing exactly the
> same bug... it still may be. However ``my'' problem does not go away
> with the mod15fix ...

Yeah, pity it did not fix it :( I will try to port Tejuns patch 
(http://home-tj.org/wiki/index.php/Sil_m15w#Patches) to 2.6.23 today or 
tomorrow. If you are testing anyway, could you then also try this?

quoted text
>
> > but as much as it fits onto the disk. On reading back this file, the
> > filesystem will report errors somewhere between 50GB and 230GB (disk size
> > is 250GB).
>
> Wow, I really see lots of corruptions (well every 1-2 GB a couple of
> bytes are corrupted). Are you getting similiarly many in the 50G - 230G
> region?
>
> > > Thanks.  I'll try to reproduce the problem here.  What's your
> > > motherboard?
> >
> > All tested S2882 boards here.
>
> I assume all equipped with lots of memory and mostly empty pci slots?

Yes, all pci-slots are free and the systems to have between 4 and 16GB memory 
(ecc, monitored with edac). Well, those are cluster systems (actually tyan 
names those B2882).
Do you think the configuration is related? Here it also happens with odirect, 
we tested this to minimize memory effects.


Cheers,
Bernd


-- 
Bernd Schubert
Q-Leap Networks GmbH
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