Message-ID: <1517916261.2849.23.camel@cybertec.at>
Subject: Re: PostgreSQL Active-Active
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Dhandapani Shanmugam <postgresql95@gmail.com>, pgsql-admin
	 <pgsql-admin@postgresql.org>, pgsql-general@postgresql.org
Date: Tue, 06 Feb 2018 12:24:21 +0100
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Dhandapani Shanmugam wrote:
> Do we have active-active setup in postgreSQL, like we have in oracle RAC?.
> Sorry if this question has been addressed already.
> What will be best open source HA for postgresql with zero RTO and RPO.

No, PostgreSQL does not have a shared storage cluster technology like RAC,
and I don't think it ever will: too complicated, does not scale well
(cache fusion, global SCN).

The normal way is to use physical replication with some third-party
cluster software that handles the failover.

There is *always* a short down time, but it shouldn't be more than a minute.
If you need to avoid data loss, use synchronous replication, but be aware
that it requires a low latency network, else your write throughput will
be very bad.

Yours,
Laurenz Albe