Re: Postgres Replication on a different network interface

Hi Achilleas,

Thanks for quick response.

Why do you want M2 to be read/write? M2 can be just read only as a passive
hot backup.

Please see the pic. embedded. I have 2 clusters ( 1- active in one site
, 2- passive in contingency site). Within the cluster in active site I
have already configured replication and its working fine. I would like to
do the same for one of the server in contingency site.

Please help. The replication traffic, I would like to configure on a 2nd
ethernet interface i.e. connected site to site as mentioned in red color.
In active cluster , the replication between the primary and slave is done
using WAL replication and using interface (eth1-M1 to eth1-S1.
I would like t o configure either (M1-eth2 to M2-eth2 or another option
S1-eth2 to S2 eth2 or may be M1-eth2 to M2 eth2).

Please suggest.

[image: image.png]

A

On Tue, Sep 1, 2020 at 4:43 PM Achilleas Mantzios <
achill(at)matrix(dot)gatewaynet(dot)com> wrote:

> On 1/9/20 1:43 μ.μ., Sanjib Mohanty wrote:
>
> Hi Experts,
>
> I had done replication earlier in EDB 9.6 version using simple WAl
> replication.
>
> My master server is listening on localhost.
>
> Example:
> listen_addresses = 'localhost,158.245.240.209'
>
> I have another additional IP configured on my both master and slave
> servers which is a dedicated network for my replication traffic example,
>
> Primary : 172.176.43.112 , Salve: 172.198.47.101 ,
>
> Question:
>
> Can I configure this Ip only for replication ?
>
>
> Yes via pg_hba.conf
>
>
> My understanding:
>
> postgresql.conf:
>
> listen_addresses = 'localhost, < what all ips we should configure here>'
> /// Do I need to add these replication traffic ip address here?? Please
> help
>
>
> On Master
> wal_level = logical or Hot_Standby
>
> max_wal_senders = 4
>
> max_replication_slots = 4
>
>
>
>
> On Replica
> In addition to the above, the following need to be configured on the
> replica:
>
> hot_standby = on
>
> hot_standby_feedback = on
>
> pg_hba.conf:
> host replication repuser 172.198.47.101 /32 md5
>
>
> Salve:
>
> standby_mode = 'on'
>
> primary_conninfo = 'host=172.198.47.101 port=5432 user=foo
> password=foopass'
>
> restore_command = 'cp /path/to/archive/%f %p'
>
> archive_cleanup_command = 'pg_archivecleanup /path/to/archive %r'
>
>
> One more question?
>
> If I have to replicate the replication traffic from master to 2 different
> sites.
>
> Site1 ( Production) Active: One Primary (read write) M1 , 2nd one is
> Slave (read only) S1
>
> Site2(Disaster) Passive : One Primary (read write) M2 2nd one is Slave
> (read only) S2
>
> Note: I have already configured replication within the site1 , where slave
> get the wal file using wal replication.
> Question?
> Do I need to add another server as slave the Site 2 and replicate from
> the Production Primary ? what is the best practise. ?
>
>
> The sync I have plan is : M1->S1 & M2 , and then M2->S2 // please advise.
>
>
> The are a lot of things to consider and lots of choices as well.
> Availability/reliability of the master is one thing VS things that can go
> wrong in the remote network.
>
> What you have in mind (site2 : One Primary (read write)) is doable with
> logical replication which takes a different approach to physical. More
> flexible for sure but also needs more work and planing to be done.
>
> Why do you want M2 to be read/write?
>
>
>
>
>
>
> Regards,
> Sanjib
>
>
>
>
>
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>