Hello Hal, On Sat, Apr 05, 2008 at 06:19:43AM -0700, Hal Rosenstock wrote: > Hi Bernd, > > On Sat, 2008-04-05 at 00:12 +0200, Bernd Schubert wrote: > > Hello, > > > > after I upgraded one of our clusters to opensm-3.2.1 it seems to have > > gotten > > much better there, at least no further RcvSwRelayErrors, even when the > > cluster is in idle state and so far also no SymbolErrors, which we also > > have > > seens before. > > > > However, after I just started a lustre stress test on 50 clients (to a > > lustre > > storage system with 20 OSS servers and 60 OSTs), ibcheckerrors reports > > about > > 9000 XmtDiscards within 30 minutes. > > > > Searching for this error I find "This is a symptom of congestion and may > > require tweaking either HOQ or switch lifetime values". > > Well, I have to admit I neither know what HOQ is, nor do I know how to > > tweak > > it. I also do not have an idea to set switch lifetime values. I guess this > > isn't related to the opensm timeout option, is it? > > > > Hmm, I just found a cisci pdf describing how to set the lifetime on these > > switches, but is this also possible on Flextronics switches? > > What routing algorithm are you using ? Rather than play with those > switch values, if you are not using up/down, could you try that to see > if it helps with the congestion you are seeing ?
I now configured up/down, but still got XmtDiscards, though, only on one port. Error check on lid 205 (SW_pfs1_leaf2) port all: FAILED #warn: counter XmtDiscards = 6213 (threshold 100) lid 205 port 1 Error check on lid 205 (SW_pfs1_leaf2) port 1: FAILED #warn: counter RcvSwRelayErrors = 1431 (threshold 100) lid 205 port 13 Error check on lid 205 (SW_pfs1_leaf2) port 13: FAILED I'm also not sure if up/down is the optimal algorithm for a fabric with only two switches. Since describing the connections in words is a bit difficult, I just upload a drawing here: http://www.pci.uni-heidelberg.de/tc/usr/bernd/downloads/ib/Interswitch-cabling.pdf The root-guid for the up/down algorithm is leaf-5 of of the small switch. But I'm still not sure about up/down at all. Doesn't one need for up/down at least 3 switches? Something like this ascii graphic below? root-switch / \ / \ Sw-1 ------------ Sw-2 Thanks for your help, Bernd PS: These RcvSwRelayErrors are also back again. I think this occur on some operations of Lustre. Even if these RcvSwRelayErrors are not critical, they are still a bit annoying, since they make it hard to find other errors in the output ob ibcheckerrors. If we can really ignore these errors, I will write a patch to not display these by default. _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
