[DRBD-user] "local disk flush failed with status -5" on LVM

Iustin Pop iustin at google.com
Sat May 10 12:28:00 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Philipp Reisner wrote:
> Am Sonntag, 4. Mai 2008 02:19:12 schrieb Wolfgang Denk:
> > Hi,
> >
> > I'm trying to run DRBD on top of a LV, and get flooded with above
> > error messages. I know this has been discussed before, see threads
> > starting at
> > http://lists.linbit.com/pipermail/drbd-user/2008-February/008665.html
> > and
> > http://lists.linbit.com/pipermail/drbd-user/2008-February/008519.html
> >
> > When this was discussed in February, it sounded (at least to me) as is
> > a fix was on the way, see
> > http://lists.linbit.com/pipermail/drbd-user/2008-February/008692.html
> >
> > However, even top of tree from the git repo still shows the same
> > behaviour.
> >
> > Am I missing something, or is this usage mode so exotic  that  nobody
> > cares?
> >
> 
> Hi Wolfgang,
> 
> That is actually a kernel bug, I think in 2.6.24. Was fixed later, do not
> know by heart with which "sucker" release. I guess it is fixed in 2.6.25.
> 
> Starting with 8.0.12 we offer a workaround for this in DRBD (and 8.2.6 
> when I finally find the time to finish it):
> 
>   Add no-disk-flushes and no-md-flushes to your disk config.

Because this happens not only with LVM, but with any I/O subsystem that
returns wrong error codes from flushes (e.g. broken scsi drivers or
controller, I think), would it be a sane thing to disable barriers
automatically if there after a certain number of errors?

(Looking at the barrier flush code I see that only the drbd_receiver.c
has code for auto-disabling in case of EOPNOTSUPP, but drbd_actlog and
drbd_bitmap.c don't; maybe these too should have this).

The reason I propose this is because with many deployments on different
machines it would be better to let it always enabled at startup and
allow it to autodisable if it see EOPNOTSUPP or too many other errors.
And people can't always track latest upstream kernel...

thanks,
iustin



More information about the drbd-user mailing list