Lustre devel - Jul 2010 - dealloc in 1.8.4 and RHEL5.5

Hi all,

I see that dealloc is disabled in 1.8.4 by default also for RedHat kernels. I 
think it is a good idea to do that for RHEL 54 kernels, as I run into slight 
filesystem corruption on our test cluster, which I cannot explain except that 
the filesystem might have caused it. That was with 1.8.3 and ext4-ldiskfs with 
enabled dealloc.

Now my question is if dealloc really should be disabled for 1.8.4, as it will 
be based on RHEL 5.5 kernels. And as ext4 in 5.5 is based on 2.6.32, dealloc 
should work without much risk, shouldn''t it? Or does it just need some 
testing? Unfortunately, I do not have a suitable reproducer for the issue 
above.


Thanks,
Bernd



-- 
Bernd Schubert
DataDirect Networks

On Thursday, July 29, 2010, Bernd Schubert wrote:
> Hi all,
> 
> I see that dealloc is disabled in 1.8.4 by default also for RedHat kernels.
> I think it is a good idea to do that for RHEL 54 kernels, as I run into
> slight filesystem corruption on our test cluster, which I cannot explain
> except that the filesystem might have caused it. That was with 1.8.3 and
> ext4-ldiskfs with enabled dealloc.
> 
> Now my question is if dealloc really should be disabled for 1.8.4, as it
> will be based on RHEL 5.5 kernels. And as ext4 in 5.5 is based on 2.6.32,
> dealloc should work without much risk, shouldn''t it? Or does it
just need
> some testing? Unfortunately, I do not have a suitable reproducer for the
> issue above.
I think I see what is still missing - quota related dealloc patches have not 
been merged according to the 5.5 ext4 patch description.



-- 
Bernd Schubert
DataDirect Networks