Re: Multiple Server Installation/Design Question.

On Mon, Feb 15, 2010 at 9:01 AM, Ozz Nixon <ozznixon(at)gmail(dot)com> wrote:
> Hello,
>
>        I have been experimenting with the product, nicely done! I would like
> to implement it in a live scenario now, however, I have questions.
>
> I have 2 Data Centers, 1 with 2 ISPs and 1 with 1 ISP. I would like to setup
> the product to replicate from 1 center to another - as close to real-time as
> possible. I am sure I can find the steps to do this, however, any
> information would be nice.
>
> The question is, the Data Center with 2 ISPs, has a common Drive Array [NFS
> based] and I would like to install the "engine" on each Blade Server,
> however, have the same database files used by the engines. Is this possible?

No, and often using NFS has its own set of issues to deal with, mostly
to do with durability.

> Details of Data Center #1:
> ISP #1 - Windows Server, 1TB Drive - All Internal.
>
> Details of Data Center #2:
> ISP #2 - Windows Server, 4TB Drive Array - NFS Mount
> ISP #3 - Linux Server, same 4TB Drive Array - NFS Mount
>
> -- If Windows is an issue, I can easily put these on Linux (running CentOS

Windows isn't the most performant OS for pgsql, but it works well
enough for most situations. The real issue is that things like slony
(replication) may not work as well or be as up to date, since it's
developed on unix.

> 5).
>
>        * My first task will be to implement a few tables with minimal
> changes occurring, replicating between the two Centers, but again DC2 has 2
> Internet Feeds. -- Think of the environment as a Wiki. Mostly searches, with
> few changes or add.
>
>        * The next project after this one will be a Message Forum solution -
> so it will have more writes then the Wiki solution - but still be a
> search/view environment.
>
>        Unfortunately, I need to have a solution in testing this week - due
> to the heavy snow storms up north, today is the first day I have had access
> to the Internet to start asking question.

The three replication systems most posted about and apparently in
common use are Slony (complicated, versatile) londiste (simple, not
quite as versatile) and bucardo which I'm not all that familiar with,
but it looks interesting.