Re: adding a bdr node using bcv backup

Hi Craig, how are you?

Thanks for your answer. It doesn't seems too complex... Also, it's just a
test scenario, I don't intend to use as a production setup or to recommend
as such, at least not until I'm 100% sure I got it right...

So, assuming I get the snapshot right... The steps would be...

1) create replication slots on prior nodes before taking the snapshot (not
sure how to do that, which command would it be? );
2) take the snapshot;
3) bring it up on another server;
4) use bdr_init_copy

I'm not at work right now, but I remember two things...

On node 3 I brought up the copy, if I try get local node name, it says
node1, which is the node I got the copy from, ... Wouldn't I also have to
do something about that? Like, delete the previous information on bdr
database that went along?

Em qui, 21 de jan de 2016 00:50, Craig Ringer <craig(at)2ndquadrant(dot)com>
escreveu:

> On 21 January 2016 at 08:29, (Daniel Stolf) <dstolf(at)gmail(dot)com> wrote:
>
>> Hello there...
>>
>> I'm new to postgres and I'm trying out BDR replication...
>>
>> I know that when I issue the bdr.bdr_group_join command, it will copy the
>> entire database from the host I specify on parameter 'join_using_dsn' and
>> this may take a while depending on the network and the size of the
>> database...
>>
>> What I wanted to know is if I can leverage a bcv backup... Is it possible?
>>
>
> BCV seems to be an EMC backup system. It looks like a snapshot. If the
> snapshot taken is consistent and atomic, and if it includes both pg_xlog
> and the rest of the datadir and all tablespaces in the SAME snapshot taken
> at the SAME instant, then you can treat it much like a pg_basebackup. In
> that case you can use bdr_init_copy to bring it up as a new BDR node. You
> must either stop all writes to all other nodes or pre-create the
> replication slots *before* taking the snapshot though, otherwise the new
> node won't be able to catch up to writes done after the snapshot and before
> it was started.
>
> If this sounds too complex then stick to the documented methods that work.
> Working from separately taken snapshots is hard to get right and could lead
> to subtle data problems if you get it wrong.
>
> --
> Craig Ringer http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Training & Services
>