Thread: PostgreSQL Scalable ?

PostgreSQL Scalable ?

From
Hervé Piedvache
Date:
Hi,

One other small question ... Does PostgreSQL is scalable ?
I mean ... is it possible to have two servers, one rack of disks connected to
the 2 servers to get access in same time to the same database ?

Other point is there any possibilties to make servers clusters with PostgreSQL
? If no why ? If yes how ? ;o)

To be clear I would like to make a system with PostgreSQL able to answer about
70 000 000 requests by day (Internet services) ... I'm not sure about the
server configuration I have to make.

Thanks per advance for your answers.

Regards,
--
Hervé Piedvache

Elma Ingénierie Informatique
6 rue du Faubourg Saint-Honoré
F-75008 - Paris - France
Pho. 33-144949901
Fax. 33-144949902


Re: PostgreSQL Scalable ?

From
Jeff
Date:
On Fri, 10 Oct 2003, [iso-8859-15] Herv� Piedvache wrote:

> One other small question ... Does PostgreSQL is scalable ?
> I mean ... is it possible to have two servers, one rack of disks connected to
> the 2 servers to get access in same time to the same database ?

No. You need to replicate the DB to another machine to have this work -
and even still, all writes need to go to the 'master' db. Reads can go to
either.

> To be clear I would like to make a system with PostgreSQL able to answer about
> 70 000 000 requests by day (Internet services) ... I'm not sure about the
> server configuration I have to make.
>

Well, 70M requests/day is only about 810 / second - assuming we're talking
about simple selects that is very easy to achieve.

Considering hardware you should look at: multiple cpus, gigs of memory,
and very fast disks. (Raid5 w/battery backed write caches seem to be
popular).

You should also look at how much data this guy will hold, what is the
read/write ratio and all the "normal" things you should do while planning
a db.

--
Jeff Trout <jeff@jefftrout.com>
http://www.jefftrout.com/
http://www.stuarthamm.net/



Re: PostgreSQL Scalable ?

From
Josh Berkus
Date:
Herve'

> One other small question ... Does PostgreSQL is scalable ?

Given that we have several members of our community with 2TB databases, and
one entitiy with a 32TB database, I'd say yes.

> I mean ... is it possible to have two servers, one rack of disks connected
> to the 2 servers to get access in same time to the same database ?

Not at this time, no.

> Other point is there any possibilties to make servers clusters with
> PostgreSQL ? If no why ? If yes how ? ;o)

Only via replication or creative use of DBLink.   Nobody has yet offered to
build us database server clustering, which would be very nice to have, but
would require a substantial investment from a corporate sponsor.

> To be clear I would like to make a system with PostgreSQL able to answer
> about 70 000 000 requests by day (Internet services) ... I'm not sure about
> the server configuration I have to make.

That sounds doable on proper hardware with good tuning.    Might I suggest
that you consider hiring a consultant and start from there?  I believe that
Afilias Limited (www.afilias.info) has the requisite experience in Europe.

--
Josh Berkus
Aglio Database Solutions
San Francisco

Re: PostgreSQL Scalable ?

From
James Rogers
Date:
On Fri, 2003-10-10 at 10:41, Josh Berkus wrote:
> Herve'
> > One other small question ... Does PostgreSQL is scalable ?
>
> Given that we have several members of our community with 2TB databases, and
> one entitiy with a 32TB database, I'd say yes.


It depends on what is meant by "scalable".  In terms of physical data
size, definitely yes.  In terms of concurrency, it is also pretty good
with only a few caveats (e.g. large SMP systems aren't really exploited
to their potential).  However, in terms of working set size it is only
"fair to middling", which is why I'm looking into those parts right now.
So "scalable" really depends on what your load profile looks like.  For
some load profiles it is extremely scalable and for other load profiles
less so, though nothing exhibits truly "poor" scalability that I've
found.  A lot of scalability is how you set the parameters and design
the system if the underlying engine is reasonably competent.  For the
vast majority of purposes, you'll find that PostgreSQL scales just fine.

Cheers,

-James Rogers
 jamesr@best.com