Re: Best approach for multi-database system

Em 10/03/2016 17:18, Andy Colson escreveu:
> 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
>
>

Sorry for toppost. This is the only list I've this rule, and sometimes I
just forget...
I'll learn about replication slots.
Thanks for the tip.

Regards,

Edson Richter