[Linux-cluster] RHEL3 Cluster Heart Beat Using Cross Over Cable

[Nathan Nobbe]

On Thu, Nov 6, 2008 at 10:38 AM, Rick Stevens <ricks at nerd.com> wrote:

> lingu wrote:
>
>> 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:
>>
>> 192.168.1.2 --node 1 physical ip  with  class c subnet (bond0 )
>> 192.168.1.3 --node 2 physical ip  with class c subnet (bond0 )
>> 192.168.1.4  --- 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.
>>
>
> 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.


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
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