[Spread-users] New to spread and got some problems

[Jeremy James]

Tobias Stocker wrote:
> Guess what. I'm damn stupid. Changed the Spread_Segment to x.y.z.63
> (because this is the broadcast) and it works. I'm very sorry for that
> foolish mistake.

My bad - I should have spotted that too. Thanks Yair!

Yair Amir wrote:
> As a temporary fix (which will work with about the same performance as long
> as you have 2 machines) you can use the following in the configuration file:
> 
> Spread_Segment 0.0.0.0:4803  {
>           node01           x.y.z.10
> }
> 
> Spread_Segment 0.0.0.0:4803  {
>           node02           x.y.z.20
> }
> 
> This will declare 2 segments, forcing Spread to use unicast between them.
> 

Out of interest, what sort of network traffic would you expect if you
have two segments, eg:

Spread_Segment 192.168.1.255:4803 {
  node1   192.168.1.1
  node2   192.168.1.2
  node3   192.168.1.3
}

Spread_Segment 192.168.2.255:4803 {
  node4   192.168.2.1
  node5   192.168.2.2
  node6   192.168.2.3
}

Would node1 broadcasting a message send packets to 192.168.1.255 and
192.168.2.255 or all of 192.168.1.255, 192.168.2.1, 192.168.2.2 &
192.168.2.3 (*)?

I have two clusters of machines in different datacentres (<10ms) and
currently don't link them together with spread. What level of
unnecessary extra traffic would I see between them if I configured the
machines in this way? If there is going to always be additional traffic,
I'll have to look at setting up a GRE tunnel for some specific multicast
traffic.

-jeremy


(*) Of course, I appreciate the real way of finding out would actually
be 1) Read the code, 2) Try it out on unsuspecting hosts...