I think there is a bit of confusion here. The MDS is doing the initial authorization for the file, using l_getgroups to access the group information from LDAP (or whatever database is used).
Daniel's point was that after the client has gotten access to the file, it will cache this file locally until the lock is dropped from the client. Cheers, Andreas On 2010-09-24, at 7:58, Tina Friedrich <tina.friedr...@diamond.ac.uk> 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. >> _______________________________________________ >> Lustre-discuss mailing list >> Lustre-discuss@lists.lustre.org >> http://lists.lustre.org/mailman/listinfo/lustre-discuss >> > > > -- > Tina Friedrich, Computer Systems Administrator, Diamond Light Source Ltd > Diamond House, Harwell Science and Innovation Campus - 01235 77 8442 > > -- > This e-mail and any attachments may contain confidential, copyright and or > privileged material, and are for the use of the intended addressee only. If > you are not the intended addressee or an authorised recipient of the > addressee please notify us of receipt by returning the e-mail and do not use, > copy, retain, distribute or disclose the information in or attached to the > e-mail. > Any opinions expressed within this e-mail are those of the individual and not > necessarily of Diamond Light Source Ltd. > Diamond Light Source Ltd. cannot guarantee that this e-mail or any > attachments are free from viruses and we cannot accept liability for any > damage which you may sustain as a result of software viruses which may be > transmitted in or with the message. > Diamond Light Source Limited (company no. 4375679). Registered in England and > Wales with its registered office at Diamond House, Harwell Science and > Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom > > > > > _______________________________________________ > Lustre-discuss mailing list > Lustre-discuss@lists.lustre.org > http://lists.lustre.org/mailman/listinfo/lustre-discuss _______________________________________________ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
