[Gluster-users] Slow write times to gluster disk

[Pat Haley]

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
Center for Ocean Engineering       Phone:  (617) 253-6824
Dept. of Mechanical Engineering    Fax:    (617) 253-8125
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