[Spread-users] Spread_Segment question

[Theo Schlossnagle]

On Mar 5, 2004, at 4:50 AM, Jeffrey ALDERMAN wrote:

> Hi All,
> I am running Spread 3.17.1 on 3 Mandrake 9.2 Linux boxes (all on the 
> same network) for use by Zope Replication Services 1.3.   I need to 
> run at least the 9 hosts below (three on each physical machine) and 
> preferably many more.
>  
> With the configuration below 2 of the 3 machines' Spread daemons fire 
> up ok, the last doesn't (I don't know where any spread logs are being 
> saved to give more help).

What exactly did you hope to accomplish by specifying the same machine 
more than once in a single Segment? (it is not possible)

Spread is a communications bus.  You only need one daemon running on 
each machine.  Assuming you can configure the group that Zope uses to 
perform its replication, all the Zope setups can use the same Spread 
ring.

If Zope replication must have a "dedicated" spread ring, you will need 
to run three different instances of Spread on each machine each with a 
different configuration file.  Each configuration file will need the 
three related machines in it but you will need to use a _different_ 
port than 4803.  Also, note that Spread will use more than just port 
4803 in the below configuration (I think 4804 and 4805 -- maybe just 
4804).  When we run two different rings, we run them on ports: 4903, 
4913, 4923 to make it easy to remember and allow enough "space" for 
Spreads extra port use.

In most cases, you have nothing to gain by running multiple rings.  
However, it _can_ contribute to stability in very high traffic 
environment and it allows for simple upgrades.  We flip back and for 
between 4903, 4913, 4923 and 4803, 4813, 4823 when we upgrade Spread -- 
out clients are designed to try one and then they other on failure -- 
automatically, so assuming client backward compatibility, it requires 
just bring up and new upgraded ring, testing and simply shutting off 
the old ring.

>  
> Spread_Segment xxx.xxx.xxx.255:4803 {
>       si1pro xxx.xxx.xxx.142
>       va1pro xxx.xxx.xxx.143
>       is1pro xxx.xxx.xxx.144
>       si1dev xxx.xxx.xxx.142
>       va1dev xxx.xxx.xxx.143
>       is1dev xxx.xxx.xxx.144
>       si1sta xxx.xxx.xxx.142
>       va1sta xxx.xxx.xxx.143
>       is1sta xxx.xxx.xxx.144
> }
>  
> However, if I take out 3 of the above hosts all 3 machines run Spread 
> fine. 
>   
> Does anyone know of a limit to the number of hosts that can be 
> declared in this section?  Or should multiple Zope Replication 
> Instances (not that people here should know about ZRS but it is the 
> client to Spread in this case) be able to work using only 1 hostname 
> per machine
> for example:
>  
> Spread_Segment xxx.xxx.xxx.255:4803 {
>       si1pro xxx.xxx.xxx.142
>       va1pro xxx.xxx.xxx.143
>       is1pro xxx.xxx.xxx.144
> }
> I also tried splitting the hosts up into 3 separate Spread_Segment 
> entries (see below) with the same broadcast address but on a different 
> port number but that didn't seem to work either.
>
>  
> Spread_Segment xxx.xxx.xxx.255:4803 {
>       si1pro xxx.xxx.xxx.142
>       va1pro xxx.xxx.xxx.143
>       is1pro xxx.xxx.xxx.144
> }
>
> Spread_Segment xxx.xxx.xxx.255:4805 {
>       si1dev xxx.xxx.xxx.142
>       va1dev xxx.xxx.xxx.143
>       is1pro xxx.xxx.xxx.144
> }
> Spread_Segment xxx.xxx.xxx.255:4807 {
>       si1sta xxx.xxx.xxx.142
>       va1sta xxx.xxx.xxx.143
>       is1sta xxx.xxx.xxx.144
> }
>
> I do run a firewall on each of the three machines but all the ports 
> used by these configs are allowed in and out (4803-4808).
>  
> Many thanks for your time,
>  
> Jeff.
>
// Theo Schlossnagle
// Principal Engineer -- http://www.omniti.com/~jesus/
// Postal Engine -- http://www.postalengine.com/
// Ecelerity: fastest MTA on Earth
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 6357 bytes
Desc: not available
Url : http://lists.spread.org/pipermail/spread-users/attachments/20040305/40f90af0/attachment.bin