On Fri, Sep 11, 2009 at 1:46 PM, Eric Chris Garrison <[email protected]> wrote: > Okay, we "solved" the ADS/MTU problem for one supercomputer... what it > turned up was that our AFS servers were only able to do 1500 MTU, but the > router they were on accepted jumbo (9000 MTU) frames and passed them on, > so they fragmented. We had them set up our VLAN to not accept jumbo > frames, and that supercomputer cluster was up and running fine. > > However, there's another supercomputer that had similar problems that were > NOT solved by this. In fact, the problem there turns out to be > fragmentation during aklog when talking to the AD servers, not when > talking to our AFS servers. > > The traceroute shows that the DF (do not fragment) flag is set, and a > packet of 2441 was being sent, which is bigger than 1500. It's > fragmenting somewhere closer to the ADS servers, which are themselves set > to 1500 MTU, according to their admins. > > So is the DF flag necessary? If not, how can we change that?
AFS isn't setting DF in Kerberos traffic, so necessary or not, it's not directly our fault, at least, assuming this is as I read it, aklog failing. _______________________________________________ OpenAFS-info mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-info
