Re: 9.1.3 Standby catchup mode

On 04/08/2012 03:51 AM, hans wulf wrote:
>> Why would you not want to maintain a WAL archive? Are you depending on
>> the
>> slave server(s) as your only form of backup?
>
> If the slave devide acts as a perfect backup, why would I need an additional 3rd entiy for WAL backups?

Belt and suspenders mode:). Assuming you archive the WAL files to a
third machine and there is independent connection from that machine to
the standby, the standby will pick up the data from those WAL files if
it loses its streaming connection to the primary and the primary is
still up and generating WAL files. This would depend on you setting up
file archiving from the primary to the third machine and archive
retrieval from the third machine to the standby. What you get is a
history of WAL files that you can replay should the streaming link go
down. Basically a second copy of the primary.

>
> I know what the difference between sync and async is, but I don't see the need for a WAL archive in sync mode. Can you please explain that? Thanks

>
>

--
Adrian Klaver
adrian(dot)klaver(at)gmail(dot)com