Обсуждение: PostgreSQL Scalable ?
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
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/
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
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