Re: Restart replicated slave procedure

On Sat, Aug 23, 2014 at 2:18 AM, Joseph Kregloh <jkregloh(at)sproutloud(dot)com>
wrote:

>
>
> On Fri, Aug 22, 2014 at 2:21 PM, Jerry Sievers <gsievers19(at)comcast(dot)net>
> wrote:
>
>> Joseph Kregloh <jkregloh(at)sproutloud(dot)com> writes:
>>
>> > Hi,
>> >
>> > Currently I am doing asynchronous replication from master to
>> > slave. Now if I restart the slave it will fall out of sync with the
>> > master. Is there a correct procedure or set of steps to avoid this? I
>> > am looking for best practices or suggestions. Whenever my slave fell
>> > out of sync I would either issue a new pg_base_backup() or set the
>> > master to pg_start_backup() do an rsync and stop using
>> > pg_stop_backup(). If there is a way to avoid any of that, for example
>> > pause replication to hold all the wal files until the replicated slave
>> > comes back and then release them once the replicated slave is up.
>> >
>> > I apologize if this question has already been asked. I did some
>> searching beforehand.
>>
>> See the manual and read up on the 2 GUCs; archive_command and
>> wal_keep_segments.
>>
>>
> Thanks, i'll read into this some more.
>
>
>> wal_keep_segments lets you hold a configurable number of WAL segments
>> back and buy some more time till you have to resync the stand bys.
>>
>> Setting archive_command to '' or something like '/bin/false' lets you
>> delay archiving forever till you change them back again and/or fill
>> whatever file system pg_xlog writes to :-)
>>
>>
> So disabling the archive_command by setting it to and empty string or
> /bin/false will effectively pause log shipping? When I re-enable the
> archive command will it continue where it left of when the archive_command
> was "disabled"?
>
>
AFAIK, disabling archive_command will result on accumulated wal files on
xlog dir on master. And when You re-enable the archive_command, it will
continue where it left of. It has the status of last archived wal files.
Check on PGDATA/pg_xlog/archive_status/

>
>
>> >
>> > Thanks,
>> > -Joseph Kregloh
>> >
>>
>> --
>> Jerry Sievers
>> Postgres DBA/Development Consulting
>> e: postgres(dot)consulting(at)comcast(dot)net
>> p: 312.241.7800
>>
>
>

--
Regards,

Soni Maula Harriz