[Lustre-discuss] e2scan wrong file list mtime/ctime

[Andrea Pieretti]

Dear Andreas, sorry for the delay,
I work with Miguel, so i'll write for him.

We have one question,
is it possible (safe) to use debugfs on a mounted Lustre filesystem?

Thanks

Andrea



Andreas Dilger wrote:
> On 2009-12-16, at 06:28, Miguel Molowny Lopez wrote:
>   
>> we are running lustre 1.8.1.1 on our storage cluster based on IB.
>>
>> We are building a "bulldozer" for a scratch area and we have found an
>> odd behaviour in the e2scan utility (maybe a bug or a ... "defined
>> behaviour" we don't know about).
>>
>> We have reproduced this behavior several time and we are having these
>> results:
>> - we run e2scan on the MDT to have the files newer than 3 days ago:
>>   command line used was like:
>>     * e2scan -l -N '2009-12-13' /dev/mapper/mdt
>>     or:
>>     * e2scan -l -n /tmp/file.timestamp /dev/mapper/mdt
>>       where file.timestamp has been created with the date of
>>       3 days ago using touch
>>   The result is sorted and saved in a file called: 3daysago.list
>> - we then run another e2scan looking for files newer than 2 days ago
>>   using the same command line and the result is sorted and saved in
>>   a file called: 2daysago.list
>>
>> The problem is that there are files whose last modification time is
>> before the date at which we run the two e2scan commands (they were not
>> modified during the run of e2scan) _BUT_ they appear only in the list
>> 3daysago.list. Here is an example:
>>
>> - first run of e2scan at: Dec 15 16:20 (produce list 3daysago.list)
>> - second run of e2scan at: Dec 15: 16:50 (produce list 2daysago.list)
>> - file: /scratch/foobar.txt has mtime=ctime = Dec 14 03:19
>>
>>   This file is still on filesystem after the run of the two e2scan cmd
>> well, this file appears only in the 3daysago.list. And this happen for
>> a _LONG_ list of files.
>>     
>
>
> This is definitely odd.  It is worthwhile to check what the timestamp  
> is on the MDS, via "debugfs -c -R 'stat foobar.txt'", in addition to  
> checking via "stat /scratch/foobar.txt" in the filesystem.
>
> Cheers, Andreas
> --
> Andreas Dilger
> Sr. Staff Engineer, Lustre Group
> Sun Microsystems of Canada, Inc.
>
> _______________________________________________
> Lustre-discuss mailing list
> Lustre-discuss at lists.lustre.org
> http://lists.lustre.org/mailman/listinfo/lustre-discuss
>   

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