<div class="gmail_quote">On Thu, Nov 6, 2008 at 10:38 AM, Rick Stevens <<a href="mailto:ricks@nerd.com">ricks@nerd.com</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> <div class="Ih2E3d">lingu wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Hi, I am running two node active/passive cluster running RHEL3 update 8 64 bit OS on Hp Box with external hp storage connected via scsi. My cluster was running fine for last 3 years.But all of a sudden cluster service keep on shifting (atleast one time in a day )form one node to another. After analysed the syslog i found that due to some network fluctuation service was getting shifted.Both the nodes has two NIC bonded together and configured with below ip. My network details: <a href="http://192.168.1.2" target="_blank">192.168.1.2</a> --node 1 physical ip with class c subnet (bond0 ) <a href="http://192.168.1.3" target="_blank">192.168.1.3</a> --node 2 physical ip with class c subnet (bond0 ) <a href="http://192.168.1.4" target="_blank">192.168.1.4</a> --- floating ip ( cluster ) Since it is a very critical and busy server may be due to heavy network load some hear beat signal is getting missed resulting in shifting of service from one node to another. So i planned to connect crossover cable for heart beat messages, can any one guide me or provide me the link that best explains how to do the same and the changes i have to made in cluster configuration file after connecting the crossover cable. </blockquote> </div> The crossover cable is pretty easy to make and a lot of places have ones prebuilt. If you want to make one yourself, you're interested in the orange pair of wires (normally pins 1 and 2) and the green pair of wires (normally pins 3 and 6). The blue and brown pairs don't do anyting in standard TIA-56B cables. The wiring diagram is: End "A" (std) End "B" (crossover) pin 1 Orange/White pin 3 pin 2 Orange pin 6 pin 3 Green/White pin 1 pin 4 Blue pin 4 pin 5 Blue/White pin 5 pin 6 Green pin 2 pin 7 Brown/White pin 7 pin 8 Brown pin 8 Remember that the pins are numbered from the left, looking at the hole the cable goes into with the latch on the bottom. I generally put some sort of rather blatant mark on any such cable such as a big piece of tape or coloring the ends with a red marker so it's obvious that the cable is "special". To use it, just plug one end of the cable into the cluster NIC of the first system and the other end into the cluster NIC of the second system. You should get link lights at both ends.</blockquote><div> many modern machines will work w/o a crossover cable. ive got 2 dell 1650s running heartbeat / drbd over a direct connection for heartbeat communication. i dont need to use a crossover on the 1650s for the direct connection to work, and those boxes are pretty old by now. so long story short, probly worth saving a little hassle and just trying a regular cat-5 cable for the direct connection. or if its a requirement for you hardware you can pick up a 3 foot crossover at radio shack, bust buy etc, for less than 10 bucks. -nathan </div></div>