[Fedora-directory-users] Command-line Consumer Initialization

[Mike Jackson]

Gordon Messmer wrote:
> Chris St. Pierre wrote:
> 
>> You'll want to set up two-way replication agreements between each pair
>> of hosts in your setup.  So if you had A, B, C, and D, you'd set up
>> agreements between A-B, A-C, A-D, B-C, B-D, and C-D.
>>   
> 
> 
> The documentation contradicts you.  Look at the second figure in the 
> "Multi-Master Replication" section of the admin manual (hard to see), 
> and the section "Configuring 4-Way Multi-Master Replication" several 
> pages below it:
> http://www.redhat.com/docs/manuals/dir-server/ag/7.1/replicat.html#1101818
> 
> The admin manual suggests a ring topology (and two agreements per set of 
> peers) for multi-master agreements.  You should have agreements between 
> A->B, A->D, B->A, B->C, C->B, C->D, D->C, and D->A.

Ring-topology survives 1 server failure, but not two. You need to 
understand your high-availability requirements to decide which is right 
for you.

Full-mesh replication supports 2 servers failing at the same time, but 
increases replication traffic.

Mininum level of agreements for 4-way MMR:
1 <-> 2
1 <-> 3
2 <-> 4


Maximum level of agreements (full-mesh) for 4-way MMR (each machine 
replicates to 3 targets):
1 <-> 2
1 <-> 3
1 <-> 4
2 <-> 3
2 <-> 4
3 <-> 4

Again, it's much easier to visualize when you draw numbered boxes on 
paper and connect the dots :-)

The systems I design require high-availability for writes, so I use 
full-mesh MMR.

--
mike