Re: Best approach for multi-database system

please don't top post.
 > Em 10/03/2016 16:56, Andy Colson escreveu:
>> On 3/10/2016 1:41 PM, Edson Richter wrote:
>>> Hi!
>>>
>>> Using async replication between geographically database servers. I've
>>> some 9.3 and some 9.4 servers, so doesn't matter the version (the only
>>> reason I've not migrated all to 9.4 yet is because I'm short on time).
>>>
>>> I've experienced some synchronization failures between Master-Slave
>>> servers (for example, if connection is lost for 4 to 6 hours, the number
>>> of wall keep segments may not suffice).
>>> I've created some bash scripts that will reacreate the master-slave
>>> using rsync, which seems to be farily easy - but really slow.
>>> Depending on server size (130Gb for example) take really long on a 5Mbps
>>> link - in some cases, all night long.
>>>
>>> This is the first approach: all databases in one server, and if I loose
>>> the sync between master and slave, all data need to be transfered
>>> between server and slave and is really slow.
>>>
>>> The other approach I've tested is to split each database in one cluster.
>>> By using the second approach, I can resynch each server separeted (for
>>> example 15Gb instead 130Gb).
>>> This approach have the problema that it is needed to configure and
>>> maintain another cluster for each database.
>>>
>>> Is there a best practice for multi-database systems with async
>>> replication to avoid such "resync" problems?
>>>
>>>
>>> Thanks for your orientation,
>>>
>>
>> I wrote about my setup here:
>>
>> http://www.postgresql.org/message-id/548F3954.8040501@squeakycode.net
>>
>> Would be happy to answer questions.
>>
>> -Andy
>>
>>
>>
>
>
>

On 3/10/2016 2:14 PM, Edson Richter wrote:
 > Interesting. This logicel (only remove WAL files after been applied)
 > should be available in PostgreSQL by default.
 > I mean, to have an option wheter every 15 minutes a master server query
 > slave for completeness, or slave notify master last successfully
 > imported WAL.
 >
 >
 > Atenciosamente,
 >
 > Edson Carlos Ericksson Richter
 >


It is.  Starting in 9.4 you can use replication slots.

-Andy