[DRBD-user] DRBD Verify Log Message Out Of Sync Blocks Units

Melanie Desaive melanie.desaive at medneo.de
Thu Dec 24 08:17:46 CET 2015

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


Hello Lars,

thank you for your reply. Currently I am on christmas holidays, but I 
will look into it again, when I am back in office and reply in more 
detail then.

Only to get it right: The information I am currently still missing is:

At what numbers the sector in DRBD are starting to be counted and at 
which block number ext4 starts counting, before I can determine what 
files are concerned by the out of sync blocks.

I am not sure, but in case anyone could be using this information, I 
will give some feedback, what steps I took to identify files on out of 
sync blocks.

Wishing "Merry Christmas" to all of you!

Melanie

On 21.12.2015 12:55, Lars Ellenberg wrote:
> On Fri, Dec 18, 2015 at 11:35:43AM +0100, Melanie Desaive wrote:
>> Hi all,
>>
>> we are at the moment experiencing irregular out-of-sync blocks on
>> our highly loaded system with the nightly drbd verify jobs.
>>
>> Disconnect/connect does swiftly put the devices back into a correct state.
>>
>> Still I would like to investigate the issue and find out what files
>> are concerned by the out of sync blocks.
>>
>> Is it possible to translate the information about the start of the
>> out of sync area from the log into ext4 filesystem blocks (4 KiB)?
>> Is it maybe simply "(sectors=512 Byte) / (ext4 block size=4096 Byte)"?
>>
>> ... block drbd7: Out of sync: start=22378360, size=8 (sectors)
>
> That's linear block address sectors (512 byte),
> so if the first byte is byte number 0, this is the 4k block
> from byte offset 512 * 22378360 (exclusive)
> to 512 * (22378360 + 8) (inclusive).
>
> 	Lars Ellenberg
>
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-- 
________________________________________

medneo GmbH
Melanie Desaive

Reinhardtstr. 23-27 | 10117 Berlin

+49 (30) 814501-644

melanie.desaive at medneo.de



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