On 11-04-14 08:06 AM, Yogi Rizkiadi wrote:
> Hi,
>
>
> i want to implement project with database replication structure 3 layers
> : A->B->C, which is A is the master node, B are 60 nodes of datacenter,
> and C are 1 - 7 nodes of machines on every datacenter. So if we count it
> has more than 100 nodes.
>
> Every machines on layer C only have 1 GB of RAM and network on 3 layers
> above are perhaps unconsistent.
>
> Is it possible to use Slony-I 2.0.4 and where can i get a good example
> for doing that ?
>
> Sorry for my bad english
>
>
> Thanks,
>

I suspect that you will be able to make it work if

A) You chain/cascade things in such a way that no provider has too many 
receivers.  I don't know what the limit will be in terms of number of 
nodes per provider, you might have to experiement.

B) You might need to increase your sync interval so you are doing syncs 
less frequently.   All nodes in the cluster will be generating sync[1] 
and those events must be confirmed by all other nodes.   This cross 
chatter might add up with 100 nodes, but if you then only generate syncs 
once a minute instead of once a second on all nodes but the origin the 
number of events floating through your system will drop.

C) It is fairly important that you be careful when doing slonik 
operations that you WAIT FOR when you need to, event confirmations for 
cluster configuration might take a bit of time in a cluster this big.

[1] - 2.0.4 suffers from 
http://bugs.slony.info/bugzilla/show_bug.cgi?id=127 which prevents these 
SYNC's from being generated on some nodes.  This bug won't cause you 
problems but you should expect some changes with 100 nodes when you upgrade.

Please report back to the list on how well this work for you.  I know of 
someone who has a cascaded cluster of around 50 nodes but I'm not aware 
of anyone running a 100 node cluster.



>
> Gie
>
>
>
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