Re: [pgsql-cluster-hackers] Replication over RDMA with Infiniband orRoCE

Thanks Greg for the advice

Tony


On 3/22/17 04:57, Greg Sabino Mullane wrote:
>> Yes, we are going to implement this over Postgres' streaming replication
>> system,
>> the usecase is DR, eg: the sync between two datacenter in same city,
>> there had FC link, (Now FC could be used to extend IB network, so we are
>> going to implement the native RDMA replication for low latency purpose
>> for that case-- it is very import for some critical system, also, this
>> replication is preferred base on Postgres' stream replication )
> ...
>
> Well, I think the starting point should be, why is streaming replication
> not preferred? It's very fast and very robust.
>
>> 2.) the IB based replication system will work with current IP based
>> replication system, it mean that, in a replication system, maybe had IB
>> replication, and also had IP replication, the case1 is: NodeA to NodeB
>> to NodeC,  NodeA -IB->NodeB --IP-->NodeC ; means, NodeA to NodeB could
>> be IB base replication, it provide low latency ;     and NodeB to NodeC
>> it is based on IP, it's orig IP based replication system ;  the case2
>> is: NodeA--IB-->NodeB, NodeA--IP-->NodeC ; means NodeA to NodeB is IB
>> replication; and NodeA to NodeC is IP based replication,
>>
>> 3.) it will support sync replication and async replication ; also
>> support phy replication and logical replication .
> ...
>
> Honestly, that sounds fairly complex, for not a lot of gain, but I don't
> know that I am competely understanding your proposal. This is a very
> low-activity mailing list - what I would recommend at this point is writing
> up a concise statement about why you need this and run it up the flagpole
> to pgsql-hackers@postgresql.org. I promise you will get more of a response
> there, for better or for worse. :)
>