[DRBD-user] Uncatchable DRBD out-of-sync issue

Stanislav German-Evtushenko ginermail at gmail.com
Mon Mar 25 15:43:43 CET 2013

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


Information by that links is deeply advanced. It's difficult even to
understand how much it is related to my problem.

> So you *possibly* have ongoing data corruption
> caused by hardware, or layers above DRBD.
Any ideas how to investigate?

> Or you may just have "normal behaviour",
> and if DRBD was not that paranoid, you'd not even notice, ever.
I'm not sure it is normal because I checked a couple of
"out-of-sync" blocks with dd and md5sum. First block was
okay (md5sums matched) but another one didn't match
and had never synced until I stopped all VMs on one node
made the resource on this node secondary, disconnected,
and connected again.

Best regards,
Stanislav

On Mon, Mar 25, 2013 at 5:07 PM, Lars Ellenberg
<lars.ellenberg at linbit.com> wrote:
> On Mon, Mar 25, 2013 at 12:20:20PM +0400, Stanislav German-Evtushenko wrote:
>> Futher investigations...
>>
>> First vefification went well but then strange things started to happen.
>> Full logs are here: http://pastebin.com/ntbQcaNz
>
> ... "Digest mismatch, buffer modified by upper layers during write" ...
>
> You may want to read this (and following; or even the whole thread):
> http://www.gossamer-threads.com/lists/drbd/users/21069#21069
>
> as well as the links mentioned there
> | The Problem:
> | http://lwn.net/Articles/429305/
> | http://thread.gmane.org/gmane.linux.kernel/1103571
> | http://thread.gmane.org/gmane.linux.scsi/59259
>
> So you *possibly* have ongoing data corruption
> caused by hardware, or layers above DRBD.
>
> Or you may just have "normal behaviour",
> and if DRBD was not that paranoid, you'd not even notice, ever.
>
> Hard to know for sure from the distance.
>
> --
> : Lars Ellenberg
> : LINBIT | Your Way to High Availability
> : DRBD/HA support and consulting http://www.linbit.com
>
> DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.



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