[Gluster-users] Slow write times to gluster disk

[Pat Haley]

Hi,

I was wondering if there were any additional test we could perform to 
help debug the group write-permissions issue?

Thanks

Pat


On 06/27/2017 12:29 PM, Pat Haley wrote:
>
> Hi Soumya,
>
> One example, we have a common working directory dri_fleat in the 
> gluster volume
>
> drwxrwsr-x 22 root dri_fleat     4.0K May  1 15:14 dri_fleat
>
> my user (phaley) does not own that directory but is a member of the 
> group  dri_fleat and should have write permissions.  When I go to the 
> nfs-mounted version and try to use the touch command I get the following
>
> ibfdr-compute-0-4(dri_fleat)% touch dum
> touch: cannot touch `dum': Permission denied
>
> One of the sub-directories under dri_fleat is "test" which phaley owns
>
> drwxrwsr-x  2 phaley   dri_fleat 4.0K May  1 15:16 test
>
> Under this directory (mounted via nfs) user phaley can write
>
> ibfdr-compute-0-4(test)% touch dum
> ibfdr-compute-0-4(test)%
>
> I have put the packet captures in
>
> http://mseas.mit.edu/download/phaley/GlusterUsers/TestNFSmount/
>
> capture_nfsfail.pcap   has the results from the failed touch experiment
> capture_nfssucceed.pcap  has the results from the successful touch 
> experiment
>
> The command I used for these was
>
> tcpdump -i ib0 -nnSs 0 host 172.16.1.119 -w /root/capture_nfstest.pcap
>
> The brick log files are also in the above link.  If I read them 
> correctly they both funny times.  Specifically I see entries from 
> around 2017-06-27 14:02:37.404865  even though the system time was 
> 2017-06-27 12:00:00.
>
> One final item, another reply to my post had a link for possible 
> problems that could arise from users belonging to too many group. We 
> have seen the above problem even with a user belonging to only 4 groups.
>
> Let me know what additional information I can provide.
>
> Thanks
>
> Pat
>
>
> On 06/27/2017 02:45 AM, Soumya Koduri wrote:
>>
>>
>> On 06/27/2017 10:17 AM, Pranith Kumar Karampuri wrote:
>>> The only problem with using gluster mounted via NFS is that it does not
>>> respect the group write permissions which we need.
>>>
>>> We have an exercise coming up in the a couple of weeks.  It seems to me
>>> that in order to improve our write times before then, it would be good
>>> to solve the group write permissions for gluster mounted via NFS now.
>>> We can then revisit gluster mounted via FUSE afterwards.
>>>
>>> What information would you need to help us force gluster mounted via 
>>> NFS
>>> to respect the group write permissions?
>>
>> Is this owning group or one of the auxiliary groups whose write 
>> permissions are not considered? AFAIK, there are no special 
>> permission checks done by gNFS server when compared to gluster native 
>> client.
>>
>> Could you please provide simple steps to reproduce the issue and 
>> collect pkt trace and nfs/brick logs as well.
>>
>> Thanks,
>> Soumya
>

-- 

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Pat Haley                          Email:  phaley at mit.edu
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Dept. of Mechanical Engineering    Fax:    (617) 253-8125
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