Re: Improving Availability

Hi Guido / Richard / Scott,

What about Sequoia? Is that better or worse than pgpool?

Thanks

____________________________________________________________________
Brendan Duddridge | CTO | 403-277-5591 x24 | brendan(at)clickspace(dot)com

ClickSpace Interactive Inc.
Suite L100, 239 - 10th Ave. SE
Calgary, AB T2G 0V9

http://www.clickspace.com

On Dec 14, 2005, at 9:51 AM, Guido Neitzer wrote:

> Hi Scott, hi Richard,
>
> On 14.12.2005, at 17:30 Uhr, Scott Marlowe wrote:
>
>> This setup I'm talking about would have pgpool on each db server.
>>
>> If you meant pgpool running on both application servers, that
>> would work
>> fine with slony in the background and pgpool in load balancing
>> mode, or
>> with pgpool doing the replication.
>
> Okay, just that I get this right (have to write a business paper on
> that and they will take me by the word ...):
>
> Setup would be:
>
> Machine 1:
> - web server
> - application server connecting to "localhost --> pgpool"
> - PostgreSQL installed and accessed only via pgpool
> - pgpool installed and knowing of machine 1 and machine 2
> (replication mode)
>
> Machine 2:
> - web server
> - application server connecting to "localhost --> pgpool"
> - PostgreSQL installed and accessed only via pgpool
> - pgpool installed and knowing of machine 1 and machine 2
> (replication mode)
>
> If one machine fails, the replication is cut off, and pgpool works
> with the other machine. Okay so far.
>
> The applications only know the connection to the local pgpool, so
> they are fault tolerant as far as pgpool accepts requests.
>
> If one machine fails, the service is not down because as far as all
> the services on the remaining machines are working properly. To get
> everything back, we will have to shut down all apps and all
> databases, sync the db data directories from the working machine to
> the machine that has failed, start the dbs, start pgpool, start the
> applications.
>
> Everything correct?
>
> cug