[Gluster-devel] Re: Experience with kernel NFS reexport

[Brent A Nelson]

Further insight: the initial mtimes are correct (and probably are for 
rsync, as well); the mtimes are getting modified by self-heal.  I'm not 
sure why self-heal did anything at all, as the mirrors should have been in 
sync, but it triggers on ls and quickly changes the mtimes on the second 
half of the mirror.

Thanks,

Brent

On Wed, 13 May 2009, Brent A Nelson wrote:

> I take that back; it doesn't seem to help, at least for the initial rsync. 
> Shouldn't it, though? If a file on 1/2 of the mirror has a different mtime 
> than the file on the other half, shouldn't self-heal fix it?
>
> The early indication was that it did seem to help in the case that I manually 
> removed a file from the second half of the mirror.  With the 
> metadata-change-log option on, the file self-healed with the correct mtime; 
> without the metadata-change-log option, it did not.  I only tried it once, 
> though, so it might have just been coincidence.
>
> I also saw the mtime issue with "cp -a".  It appeared to occur in one brief 
> burst, and this burst spanned multiple mirrors (a few files created at 
> 4:46pm, all in the same specific directory, for two different mirrors and 
> different server nodes, have bad mtimes on the second half of each mirror). 
> This was far less common than rsync, however.
>
> Thanks,
>
> Brent
>
> On Wed, 13 May 2009, Brent A Nelson wrote:
>
>> Early indications are that setting "option metadata-change-log on" for 
>> cluster/replicate is a likely workaround for the mtime issue.  I'll start 
>> over, and see if the issue is truly gone with this option in place...
>> 
>> It might be worth considering defaulting this option to "on".
>> 
>> Thanks,
>> 
>> Brent
>> 
>> On Wed, 13 May 2009, Brent A Nelson wrote:
>> 
>>> On Wed, 13 May 2009, Brent A Nelson wrote:
>>> 
>>>> With regards to the incorrect modification time appearing on some files, 
>>>> I note the following:
>>>> 
>>>> ls -l on Node1 in a mirror:
>>>> 
>>>> -r--r--r-- 1 root root 40280 2008-03-17 12:03 
>>>> /disk1/glusterfs/tftpboot/hardy64/pool/main/t/tasksel/tasksel-data_2.70ubuntu4_all.deb
>>>> 
>>>> Node 2 in the same mirror:
>>>> 
>>>> -r--r--r-- 1 root root 40280 2009-05-12 19:40 
>>>> /disk1/glusterfs/tftpboot/hardy64/pool/main/t/tasksel/tasksel-data_2.70ubuntu4_all.deb
>>>> 
>>>> It appears that 1/2 of the mirror set the modification time correctly, 
>>>> but the other half did not.
>>>> 
>>> 
>>> Just a bit of additional info.  It appears that the first half of the 
>>> mirror has correct mtimes.  The second half of the mirror has wrong mtimes 
>>> on all files, but directory mtimes are fine.  When you go to view the 
>>> mtimes on the GlusterFS, sometimes you will get the mtime from one node, 
>>> sometimes the other, hence the seeming randomness.
>>> 
>>> Also, I see that zero-length files have correct mtimes on both halves of a 
>>> mirror.
>>> 
>>> Thanks,
>>> 
>>> Brent
>>> 
>> 
>