ciao Andy! - I am pinging directly to xrootd-redic.pi.infn.it (and not to the DNS RR) since I did not modify the other copy. did not want to risk too much here (for the reason I am trying to explain below) I have a doubt about the picture you sent via the link. It makes sense only if all cmsd and xrootd are equal. In our setup (with ~40 sites connected), we had before only xrootd.ba.infn.it as redir. Now we asked the sites to move to xrootd-cms.infn.it, but after two weeks ~ 50% of the sites moved (a lot of inertia, but it is difficult to go and twist arms ...). so let's suppose - xrootd.ba.infn.it has 50 servers registered in cmsd - xroot-redic.pi.infn.it has 30. what would happen if xrootd.ba.infn.it:1094 -> xrootd-redic.pi.infn.it:1213 (which can happen if I put as manager for xrootd.ba.infn.it the DNS RR...) ? the cmsd would not have all the servers registered, and hence fail can fail on a file? it can even be ok if fail means go up to the global redirector, and then down to xrootd.ba.infn.it:1213 (even if at this point a random EU or US site would be used). So, how if the picture changing if the cmsd cannot be considered identical as # of connected servers? I know the correct answer would be "force them to change", but .... ok, I guess you understand ;) thanks a lot tom On Tue, Jul 8, 2014 at 11:37 PM, xrootd-dev <[log in to unmask]> wrote: > Hi Tommaso, > > > > From: Tommaso Boccali > Sent: Monday, July 07, 2014 11:33 PM > To: xrootd/xrootd > Cc: xrootd-dev > Subject: Re: [xrootd] xrootd fallback only populates "tried" for one > redirector (#124) > > Ciao, on the CMS-Eu redirectors I implemented as explained here: > we have 2 redirectors (xrootd.ba.infn.it and xrootd-redic.pi.infn.it), > under DNS RR xrootd-cms.infn.it > > Now redirectors' configs read > > all.role manager > > The known managers > all.manager xrootd-cms.infn.it+ 1213 > all.manager meta any cms-xrd-global.cern.ch+ 1098 > > which I understand is the advised solution. What I see is strange. > if I do something like > > xrdcp -d 3 root:// > xrootd-redic.pi.infn.it//store/test/xrootd/T2_ES_IFCA/store/mc/SAM/GenericTTbar/GEN-SIM-RECO/CMSSW_5_3_1_START53_V5-v1/0013/CE4D66EB-5AAE-E111-96D6-003048D37524.root > . > > >>>>Why did you go directly to a particular redirector. Why didn’t you use > xrootd-cms.infn.it? It would seem that if you want access to one or the > other you would use the higher level name. > > and I look into the logs, I see this goes > xrootd-redic.pi.infn.it:1094 -> xrootd.ba.infn.it:1213 ALWAYS > (so indeed xrootd-redic.pi.infn.it:1213 does not seem to be serving files > at all). > If I switch off xrootd.ba.infn.it:1213, xrootd-redic.pi.infn.it:1213 > starts to serve files, but as soon as I start again xrootd.ba.infn.it:1213, > the latter gets all the traffic. > > >>>Well, I am still confused. As none of the examples use > xrootd-cms.infn.it as the target I don’t know what is going on. Going > directly to “redic” goes directly to that. > > I tried with things like > > all.manager any/all xrootd-cms.infn.it+ 1213 > > (never really understood the difference any/all, my fault ...), but this > does not seem to change the picture > > >>>There is now a good explanation of all/any in the manual (see link at > the end). However, it has nothing to do with clients so specifying all or > any will have no effect on client access. > > eventually, on xrootd-redic.pi.infn.it cmsd.log I see traffic (with > grep serving cmsd.log > ) only when the other cmsd is down ... is this expected? is there a way to > make sure > > all.manager xrootd-cms.infn.it+ 1213 > > balances the cmsd calls between RR-DNS hosts? > > >>>DNS RR is immaterial here. The above directive simply says that your > data servers have two managers (redic and ba) and they will subscribe to > both. A client needs to access these redirectors via the higher level name > (xrootd-cms) to get access to one or the other. The choice is random and > the load would be uniformly distributed to each of the xrootd front-ends > across all of the clients. In turn, those xrootd-front ends subscribe to > the cmsd back ends (one on redic the other on ba). If you specify “all” > then the xrootd front-ends will distribute the load across the two cmsd > back ends. The default, any, uses a simple fail-over model (as you saw). > The concept is described here: > > > > http://xrootd.org/doc/dev4/cms_config.htm#_Toc384307771 > > > > Andy > > — > Reply to this email directly or view it on GitHub > <https://github.com/xrootd/xrootd/issues/124#issuecomment-48402749>. > -- Tommaso Boccali INFN Pisa --- Reply to this email directly or view it on GitHub: https://github.com/xrootd/xrootd/issues/124#issuecomment-48408485 ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the XROOTD-DEV list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-DEV&A=1