Re: postgreSQL & amazon ec2 cloud

Hi,
I wanted to reply to an existing thread but it seems a new one has been
created, so I think more details are required...

I want to run my postgres DB on Amazon EC2 using a EBS persistent disk
for postgres installation. In this way data and pg_xlog will be on the
same disk. I was just wondering if also on ec2 with EBS disks having
pg_xlog on a different EBS disk could be useful.

Thanks in advance
ste

Stefano Nichele wrote:

From the (very little) work I've done with EC2, it seems that what you get
logically doesn't have much relation to what you get physically. I don't
recall any guarentee that a virtual disk is equivilent to a physical
spindle in terms of determining performance, or even that your virtual
disk will perform consistently over time. Of course, you should test a few
setups and see how they perform.

On Mon, 20 Apr 2009, Stefano Nichele wrote:

Hi Stefano

I'm intrigued with Amazon EC2 and did a little search on it.

From your experience could it be used in similar fashion as a website ->
running a Postgresql database and having users access the database through
an interface?

If so, would the users need a Java environment installed on their machines
or would the interface connect directley to Postgresql - like a website??

Bob

----- Original Message -----
From: "Stefano Nichele" <stefano.nichele@gmail.com>
To: <pgsql-general@postgresql.org>
Sent: Monday, April 20, 2009 9:26 AM
Subject: Re: [GENERAL] postgreSQL & amazon ec2 cloud

Bob Pawley wrote:

From your experience could it be used in similar fashion as a website
-> running a Postgresql database and having users access the database
through an interface?

If so, would the users need a Java environment installed on their
machines ...

um, the users would need a Java environment if they were running Java
applications.

or would the interface connect directley to Postgresql - like a website??

what 'interface' are you referring to ? a client application can
connect to a postgres server with the postgres protocol, by default over
port 5432/tcp... a client application would do this using libpq, or a
native interface like jdbc (if the client is java)

I'll run a java webapp running in tomcat connected to postgres via jdbc.
BTW, why the access method should be important ?
I mean, my main question is .... should pg_xlog be located on a
different EBS than data ?

My doubt is really about logical vs physical disk, since i think EBS is
logical and two EBS disks could be run on the same physical disk.....so
why to separate data and pg_xlog ? Is it still useful ? It 's like to
put data and pg_xlog on two partitions of the same disk.

Cheers,
ste

John R Pierce wrote:

On Mon, Apr 20, 2009 at 02:14:00PM +0200, Stefano Nichele wrote:

Do you think that it could useful mounting two different EBS to handle
data and pg_xlog ?

Testing I've participated in suggests that it helps to split pg_xlog
elsewhere. Your mileage may vary.

- Josh / eggyknap