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Hi Tommaso, The answers are interspersed. On Wed, 7 May 2014, Tommaso Boccali wrote: > This time it is about commands like > > xrootd.redirect xrootd-cms.infn.it:1094 ? /store > > what if xrootd-cms.infn.it has multiple IPs? This is not a problem. The client will unroll the IP addresses and try each one until one of them works. The server really doesn't care because the server never uses the end-point other than giving it to the client. > I tried a > > xrootd.redirect xrootd-cms.infn.it:1094+ ? /store > > and xrootd does not complain, but it is not in the manual ... Well, yes, because it's technically valid but somewhat vacuous. The code that converts the port number ignores the trailing plus sign. If you had put the plus sign after the host name (the way it done elsewhere) it would have been accepted but client would always fail to connect since there is no such hostname. > and slightly more difficult: let's say a random one is used (and you go to > the next if that is broken). What if the the two redirectors have > registered "slightly" different servers (because for example when some > servers were started, one of the RR redirectors was off). Here, we admit that this is possible but unlikely. When a redirector comes up it waits a relatively long time to make sure that the configuration stabilizes so that it is logically equivalent to its replica redirector. So, we have never found this to be an issue and we do take down reditectors to update the kernel and what-not. But let's assume that is not the case... >If the chosen one has no answer, what happens > 1) "file not found" No, the client does not try the other redirector. If there is a static redirector for this case, the client would be redirected to another redirector as a fall-back. > 2) try with the other aliased > if I am not wrong from my tests, it seems to be "1". Your tests are correct. > So it boils down to: we cannot really make sure that all the redirectors > into the RRDNS are registered to the same servers ... can that be a problem? That would be highly unlikely. If you tell your servers that all.manager rrdns+:1234 then the servers are duty bound to subscribe to all of addresses in that DNS entry and will continue trying until they succeed. This is why once you establish the DNS entry you should not dynamically change it. Bringing down redirectors and then back up is fine. Removing address from the list is fine. You can even add addresses to the list but this is more problematic because you would have to restart all of the servers to pick up the newly added address. Andy ######################################################################## 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