[Lustre-discuss] WARNING: data corruption issue found in 1.8.x releases

[Charles A. Taylor]

FWIW, we seem to be OK with just "read_cache_enable=0".   Don't know if
that is sufficient to avoid the data corruption or not.   It will have
to do though because running with "writethrough_cache_enable=0" crashes
the OSSs within a few minutes of completing recovery.

Charlie Taylor
UF HPC Center


On Wed, 2009-09-09 at 15:30 -0400, Charles A. Taylor wrote:
> 
> On Wed, 2009-09-09 at 13:23 -0600, Lundgren, Andrew wrote:
> > Does this need to be run on EACH OSS?  Is there a central way to do it on the MDS?
> > 
> > You recommend disabling the read and the write as the settings indicate or just the read as the text indicates?
> 
> A clarification would be good here.   So far, we have found that our
> OSSs crash with the recommended work-around so that is a non-starter for
> us.   If we can run with just the read_cache_enable=0 and that is
> acceptable to avoid the corruptions bug, then that would be good to
> know.
> 
> At the moment we are not even sure we can run with just
> read_cache_enable=0.   We just know that we can't run with them both
> disabled for more than a few minutes with crashing in
> obd_filter_preprw().
> 
> Charlie Taylor
> UF HPC Center
> 
> > 
> > -----Original Message-----
> > 
> > A patch is under testing and will be included in 1.8.1.1.
> > Until 1.8.1.1 is available, we recommend to disable the OSS read cache
> > feature. This feature can be disabled by running the two following
> > commands on the OSSs:
> > # lctl set_param obdfilter.*.writethrough_cache_enable=0
> > # lctl set_param obdfilter.*.read_cache_enable=0
> > 
> > This has to be done each time an OST is restarted.
> > 
> > Best regards,
> > Johann, for the Lustre team
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