Hi Andrew, that's a pity, but thank you for your confirmation on this. Ciao, Xavier. > -----Original Message----- > From: Andrew Hanushevsky [mailto:[log in to unmask]] > Sent: Saturday, August 30, 2014 3:12 AM > To: Mol, Xavier (SCC) > Cc: [log in to unmask]; Petzold, Andreas (SCC) > Subject: RE: Redirect rules based on translated paths > > Hi Xavier, > > Ah, now I understand. The match occurs *before* any name to name > translation. I suppose this is implicit as this applies to xrootd which > "namelib" applies to the oss (storage system) which id merely used by > xrootd via the ofs layer (file system). So, the answer is no, it can't be > done using the current mechanism. So, the only other way to do this is =to > come up with a custom ofs plug-in. Typically, this would be a simple > wrapper plug-in to the existing one. The CMS throttle plugin works in this > fashion and it's pretty easy to do. > > Andy > > On Fri, 29 Aug 2014, Mol, Xavier (SCC) wrote: > > > Hi Andrew, > > > > we already read the documentation about redirect and that is the reason why we thought our setup might work in the first place. > However, key information is missing in the documentation, that the paths supplied to xrootd.redirect are matched against the original > path the client delivered and not after it has been extended/changed by e.g. localroot or oss.namelib. That is the reason why the simple > idea doesn't work out as intended for us. We want to redirect the client to the right place after path modification was performed by the > CMS trivial file catalogue, applied through oss.namelib. > > > > Please tell us, if we misunderstood the documentation or point out our error in the xrootd-clustered.cfg file. > > > > Thank you for your attention. > > > > Ciao, > > Xavier. > > > >> -----Original Message----- > >> From: Andrew Hanushevsky [mailto:[log in to unmask]] > >> Sent: Friday, August 29, 2014 4:59 AM > >> To: Mol, Xavier (SCC) > >> Cc: [log in to unmask]; Petzold, Andreas (SCC) > >> Subject: Re: Redirect rules based on translated paths > >> > >> Hi Xavier, > >> > >> Indeed, you can. However, you will need to setup a simple XRootD server > >> and tell it how you want to fan-out the redirections. That will become the > >> primary point of contact and clients will be redirected as configured. You > >> use the xrootd.redirect directive to do this. The link totyhe explanation > >> is below. > >> > >> http://xrootd.org/doc/dev4/xrd_config.htm#_Toc383723530 > >> > >> Andy > >> > >> On Thu, 28 Aug 2014, Mol, Xavier (SCC) wrote: > >> > >>> Hello xrootd community, > >>> > >>> I have a question regarding the xrootd.redirect feature, similar to what was asked before in a mail from Pablo Fernandez > >> ("xrootd.redirect changing the namespace", https://listserv.slac.stanford.edu/cgi-bin/wa?A2=XROOTD-L;87c83b90.1302): Can we make > >> xrootd apply the redirect rule to a path _after_ name conversion was done? > >>> > >>> Like Pablo, we also have a dCache storage element with a xrootd data server in front of it, that will always redirect to a dCache > xrootd > >> door. This time however, we want to have the xrootd redirector choose between two different dCache instances based on the path the > >> client requests. The xrootd.redirect setting seems ideal for this, but there is one problem: When using a path with the redirect > statement, > >> this path is matched against the file name the client provided to xrootd. But we would like xrootd to match it against the PFN, that will > >> result out of the name mangling done by the CMS trivial file catalogue (TFC) (see oss.namelib in the attached cfg). It is fine that the > client > >> keeps its original file name, the very same name conversion will be done by the dCache xrootd door again. > >>> > >>> To explain our situation in more details, in case you are wondering what we tried so far... > >>> On the xrootd data server, we have mounted the dCache namespace on /pnfs/gridka.de/cms. The client usually comes with file > names > >> beginning with '/store', which the CMS TFC will change into '/pnfs/gridka.de/cms/disk-only/store' (always prepending > >> '/pnfs/gridka.de/cms/disk-only'), the PFN xrootd will perform the lookup task with. Upon successful lookup, the client will always get > >> redirected to cmsxrootd-kit.gridka.de:1094, thanks to the current active redirection rule (based on the path '/'). What we tried to do > now > >> is mounting the name space of a second dCache instance on /pnfs/gridka.de/dcms, right next to the previous one, and introduce two > >> redirection rules like this: > >>> > >>> # xrootd.redirect cmsxrootd-kit.gridka.de:1094 / > >>> xrootd.redirect cmsxrootd-kit.gridka.de:1094 /pnfs/gridka.de/cms > >>> xrootd.redirect f01-031-117-e.gridka.de:1094 /pnfs/gridka.de/dcms > >>> > >>> After restart of xrootd+cmsd, whenever we tried to read a file, the client failed in a weird way. The file lookup still was successful > (since > >> we changed nothing about that), but then an input/output error occurred for xrootd, like this one: > >>> > >>> 140827 16:57:15 807 XrootdXeq: mol.11144:[log in to unmask] login > >>> 140827 16:57:15 807 mol.11144:[log in to unmask] XrootdProtocol: endsess 409:23.6 > >>> 140827 16:57:15 807 mol.11144:[log in to unmask] ofs_open: 0-600 fn=/store/mc/Summer12/(...) > >>> Resulting PFN: /pnfs/gridka.de/cms/disk-only/store/mc/Summer12/(... > >>> 140827 16:57:15 807 mol.11144:[log in to unmask] ofs_fstat: fn=/store/mc/Summer12/(...) > >>> 140827 16:57:15 807 XrdLink: Unable to send file to mol.11144:[log in to unmask]; input/output error > >>> 140827 16:57:15 807 XrootdXeq: mol.11144:[log in to unmask] disc 0:00:00 (sendfile failure) > >>> 140827 16:57:15 807 mol.11144:[log in to unmask] ofs_close: use=1 fn=/store/mc/Summer12/(...) > >>> > >>> Yes, we made sure that the file does actually exist, before we tried to read it. Only after we reverted the redirect path back to '/' or > >> '/store', we were able to read the file again successfully. > >>> > >>> So stating the question again, can we make xrootd respect the PFN for redirect decision making? Since the PFN doesn't leave xrootd > >> anymore, that might somehow be done using a trigger we failed to find so far? > >>> > >>> Of course, if you have ideas of how we can solve the problem in a different way, please tell us. If at all possible, we would like to keep > >> this one xrootd data server and not set up a second, independent one, or introduce a xrootd manager in front of the data server. E.g. if > we > >> could somehow make xrootd perform two file lookups, then we could first try with '/pnfs/gridka.de/cms' as prefix and only if that fails, > try > >> again using '/pnfs/gridka.de/dcms' and redirect based on the results. Our expertise unfortunately is not sufficient to find a way to > achieve > >> either of the solutions. > >>> > >>> Thank you very much for your attention. > >>> > >>> Ciao, > >>> Xavier. > >>> > >>> **** > >>> Karlsruher Institute of Technology (KIT) > >>> Steinbuch Centre for Computing (SCC) > >>> > >>> B. Sc. Xavier Mol > >>> GridKa Storage Administrator and Support Manager > >>> > >>> Hermann-von-Helmholtz-Platz 1 > >>> Geb. 449 > >>> 76344 Eggenstein-Leopoldshafen > >>> Phone: +49 721 608 23041 > >>> Email: [log in to unmask] > >>> www.kit.edu > >>> KIT - University of the State of Baden-Württemberg and National Large-scale Research Center of the Helmholtz Association > >>> **** > >>> > >>> > >>> ######################################################################## > >>> Use REPLY-ALL to reply to list > >>> > >>> To unsubscribe from the XROOTD-L list, click the following link: > >>> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-L&A=1 > >>> > > ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the XROOTD-L list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-L&A=1