[DRBD-user] Mystery with online verify and Out of sync sectors.

Dimitrij Hilt dimitrij.hilt at fhe3.com
Tue Jun 17 10:03:50 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.

Florian Haas schrieb:
>> Florian Haas schrieb:
>>> OK. Can you post a relevant excerpt of your syslog? Please do "grep
>>> drbd0
>>> /var/log/syslog", and then cut & paste to include 100 or so relevant
>>> lines
>>> from your most recent verify run.
>> Sure:
>> Jun 15 10:47:48 host-a kernel: drbd0: conn( Connected -> VerifyS )
>> Jun 15 10:48:43 host-a kernel: drbd0: Out of sync: start=4475928,
>> size=32 (secto
>> rs)
>> Jun 15 10:48:43 host-a kernel: drbd0: Out of sync: start=4475960, size=8
>> (sector
>> s)
> Right. And now can you do
> dd if=<dev> skip=<start> bs=512 count=<size> iflag=direct | openssl md5
> ... where <dev> is your backing device, <start> is the first out-of-sync
> sector as reported in the kernel log, and <size> is the number of
> out-of-sync sectors?
I did it allready.
> Please do that on both nodes, for a handful (say 5 or so) of out-of-sync
> areas reported in your syslog.
> If those MD5 sums match, then these are apparently false positives and
> we'll have to look into what's causing them.
> If, however, they do not match, replace "openssl md5" with "xxd" in the
> command above, and try to interpret those hex dumps. Are they completely
> different, do they not match at all, or are you seeing just one or two
> seemingly random differences?
Yes, i saw differences. These sectors was not false positives.
> And just so I understand you correctly: you
> - unmounted your file system,
> - made both devices Secondary,
> - ran "drbdadm invalidate-remote <resource>",
> - waited for the full sync to complete,
> - ran "drbdadm verify <resource>" immediately thereafter,
> - and even then you saw these out-of-sync messages in your syslog?

At the moment the problem is away. I did:
change meta-disc to internal
disable data-integrity-alg

recreate DRBD device.

It works on both nodes now without any problems. I will this week revert
both settings and check when it happens again.



Dimitrij Hilt
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