[Lustre-discuss] need help debuggin an access permission problem

Fan Yong yong.fan at whamcloud.com
Fri Sep 24 08:59:55 PDT 2010

  In fact, the issues occurred when MDS does the upcall (default 
processed by user space "l_getgroups") for user/group information 
related with this RPC, one UID for each upcall, and all the 
supplementary groups (not more than sysconf(_SC_NGROUPS_MAX) count) of 
this UID will be returned. The whole process is not nothing related with 
single user or not. If it is the improper configuration (of LDAP) for 
some user(s) caused the failure, you have to verify all the users one by 


On 9/24/10 9:58 PM, Tina Friedrich wrote:
> Actually, what I hit was one of the LDAP server private to the MDS
> errounously had a size limit set where the others are unlimited. They're
> round robin'd which is why I was seeing an inermittent effect. So not a
> client issue, the clients would not have used this server for their
> lookups.
> Which is why I'm puzzled as to how this works, and trying to understand
> it a bit better; to my understanding, this should not affect lookups on
> single users, only 'bulk' transfers of data, at least as I understand this?
> Tina
> On 24/09/10 12:35, Daniel Kobras wrote:
>> Hi!
>> On Fri, Sep 24, 2010 at 09:18:15AM +0100, Tina Friedrich wrote:
>>> Cheers Andreas. I had actually found that, but there doesn't seem to be
>>> that much documentation about it. Or I didn't find it :) Plus it
>>> appeared to find the users that were problematic whenever I tried it, so
>>> I wondered if that is all there is, or if there's some other mechanism I
>>> could test for.
>> Mind that access to cached files is no longer authorized by the MDS, but by the
>> client itself. I wouldn't call it documentation, but
>> http://wiki.lustre.org/images/b/ba/Tuesday_lustre_automotive.pdf has an
>> illustration of why this is a problem when nameservices become out of sync
>> between MDS and Lustre clients (slides 23/24). Sounds like you hit a very
>> similar issue.
>> Regards,
>> Daniel.
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