<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> </head> <body bgcolor="#ffffff" text="#000000"> Craig White wrote: <blockquote cite="mid1195236903.1159.14.camel@cube.tobyhouse.com" type="cite"> <pre wrap="">On Fri, 2007-11-16 at 11:18 -0600, Jon Harder wrote: </pre> <blockquote type="cite"> <pre wrap="">I am having problems booting iMac clients that I believe is related to overwhelming them with data. This is what I am seeing as they boot up: ... Mounting root filesystem: /opt/ltsp/ppc from: 192.168.0.254 Doing the pivot_root nfs:server 192.168.0.254 not responding, still trying nfs:server 192.168.0.254 OK nfs:server 192.168.0.254 not responding, still trying nfs:server 192.168.0.254 OK nfs:server 192.168.0.254 not responding, still trying and these last two lines repeat indefinitely. Some searching reveals that this might be related to the old computers being overwhelmed with too much UDP nfs traffic from the server. Originally I tested this setup with a few iMac clients and it worked fine. Now that I want to roll it out, I purchased a new HP ProCurve 1800-24G switch which is apparently dumping the data from the server's Gb connection a lot faster than the switch in my original test setup was able to do. I hooked six of the iMacs to an old 8 port switch and they all boot fine. Once they were up and running, I moved the connections over to the new fast switch and they work better, but soon the oldest iMacs freeze up. One suggestion I found was to force the clients to connect to NFS using TCP instead of UDP. I tried playing with /opt/ltsp/ppc/etc/rc.sysinit a little bit to force TCP, but with no apparent success. I use tcpdump to monitor the network. The server is pushing out a lot of UDP packets! Can someone suggest what I might do to ensure the clients are using TCP? Or is there a way to throttle the server so that it only sends so much traffic to a particular client? Any help would be appreciated. </pre> </blockquote> <pre wrap="">---- Jon, I had terrible problems at first and found that the spanning tree protocol on my Dell switches had to be disabled...I found no other way around this (reliable way anyway). The way I discovered/proved the problem was to make sure that the last switch between client and server didn't have spanning tree protocol...i.e... Server -> cheap switch -> expensive switch with spanning tree -> cheap switch -> mac client Or just eliminate the expensive switch entirely from the equation and it worked fine. Then the issue is simply to disable the spanning tree protocol on your switch if that's the problem Craig</pre> </blockquote> Yep, older Macs have always had challenges with the switch running the full spanning tree algorithm. It is known to play havoc with DHCP on Macs in particular. Some switches might not let you actually disable the spanning tree protocol (STP). Cisco IOS-based switches, like 3550's, number among these. However, you can put it into what's called "fast learning" mode. Basically, this means two to four seconds instead of nearly 30 for the port to come up once you fire up the iMac client. Works like a champ. My iMac Bondi was much happier afterwards. --TP </body> </html>