Re: Postgresql in a Virtual Machine

On Tue, Nov 26, 2013 at 10:40 AM, Ben Chobot <bench(at)silentmedia(dot)com> wrote:

> On Nov 26, 2013, at 9:24 AM, Craig James wrote:
>
> So far I'm impressed by what I've read about Amazon's Postgres instances.
> Maybe the reality will be disappointing, but (for example) the idea of
> setting up streaming replication with one click is pretty appealing.
>
>
> Where did you hear this was an option? When we talked to AWS about their
> Postgres RDS offering, they were pretty clear that (currently) replication
> is hardware-based, the slave is not live, and you don't get access to the
> WALs that they use internally for PITR. Changing that is something they
> want to address, but isn't there today.
>

I was guessing from the description of their "High Availability" option ...
but maybe it uses something like pg-pool, or as you say, maybe they do it
at the hardware level.

http://aws.amazon.com/rds/postgresql/#High-Availability

"Multi-AZ Deployments – This deployment option for your production DB
Instances enhances database availability while protecting your latest
database updates against unplanned outages. When you create or modify your
DB Instance to run as a Multi-AZ deployment, Amazon RDS will automatically
provision and manage a “standby” replica in a different Availability Zone
(independent infrastructure in a physically separate location). Database
updates are made concurrently on the primary and standby resources to
prevent replication lag. In the event of planned database maintenance, DB
Instance failure, or an Availability Zone failure, Amazon RDS will
automatically failover to the up-to-date standby so that database
operations can resume quickly without administrative intervention. Prior to
failover you cannot directly access the standby, and it cannot be used to
serve read traffic."

Either way, if a cold standby is all you need, it's still a one-click
option, lots simpler than setting it up yourself.

Craig