[comp.protocols.tcp-ip] VaxCluster and rdump don't mix?

jstewart@sce.carleton.ca (John Stewart) (11/16/89)

We backup a number of Sun machines on our ethernet backbone using rdump.
While this is running the network is busy but still usable by Sun machines.
There are also 3 DEC machines on the backbone that are VaxCluster'd with
a megaton of DEC hardware in our Physics subnet (isolated from the backbone
via a Retix bridge).  The DEC machines seem to intensely dislike the network
load because they start crashing and rebooting themselves while we are
running our backups.


   Our physics people blame the problem on our backbone ethernet (and us
by insinuation as we maintain the backbone).  I think the problem lies with
the VaxCluster software but we're not a DEC shop so we can only speculate
about that.

   If anyone else has run into this problem I sure would like to hear your
advice.
-- 
"Support the President's War On Long Usenet Signatures"

Gene.Hastings@BOOLE.ECE.CMU.EDU (11/20/89)

There are a number of simple (I hope!) ideas to pursue:
(Most of them require some sort of Ethernet monitor, like PC Netwatch, FTP
Software Lanwatch, TCPdump on a Sun, or a special purpose monitor like an
Excelan Lanlyser, or a Network General Sniffer.)

Is your Retix bridge really filtering? If it is, the Physics people should
not see any non-broadcast traffic. Check the Physics cable for existence of
the rdump traffic or destination addresses that aren't on it. 

There are two things that can be affecting the VMS hosts - inordinate
amounts of broadcast traffic (which would affect any host), or VERY high
traffic on the cable, this last because of features of the way DECNET
routing updates are done.

Chances are, iff the Vax subnet is seeing your traffic (and it can't be
avoided), some help can be gained by lengthening (in NCP) the DECNET routing
period. Have them check the DECNET manuals for ranges of settings for the
announce and listen parameters.

Gene