Re: Streaming Replication archive_command is really needed?

On Thu, Jul 20, 2017 at 10:07 PM, Leonardo M. Ramé <l(dot)rame(at)griensu(dot)com> wrote:
> El 20/07/17 a las 16:57, Andreas Kretschmer escribió:
>> On 20 July 2017 21:46:09 GMT+02:00, "Leonardo M. Ramé"
>> <l(dot)rame(at)griensu(dot)com> wrote:
>>>
>>> Hi, I wonder if archive_mode=on and archive_command parameters in
>>> postgresql.conf are really needed for streaming replication between two
>>>
>>> servers (master-slave).
>>
>> No.
>
> So, can I just comment those commands and remove the main/archive directory?

"No" is not completely exact and lacks in details. There are two cases
where having an archive is helpful:
1) The standby has disconnected from its primary for a time long
enough that WAL segments have been rotated by two completed
checkpoints. If that happens, when the standby reconnects it would
fail, and you would need to take a new base backup.
2) Backup strategies. Keeping a larger history set of WAL segments is
helpful for incremental backups, which is partially the point actually
raised upthread about PITR.
--
Michael