Re: hardware and For PostgreSQL - Mailing list pgsql-performance

It would probably help you to spend some time browsing the archives of
this list for questions similar to yours - you'll find quite a lot of
consistent answers. In general, you'll find that:

- If you can fit your entire database into memory, you'll get the best
   performance.

- If you cannot (and most databases cannot) then you'll want to get the
   fastest disk system you can.

- For reads, RAID5 isn't so bad but for writes it's near the bottom of the
   options. RAID10 is not as efficient in terms of hardware, but if you
   want performance for both reads and writes, you want RAID10.

- Your RAID card also matters. Areca cards are expensive, and a lot of
   people consider them to be worth it.

- More procs tend to be better than faster procs, because more procs let
   you do more at once and databases tend to be i/o bound more than cpu
   bound.

- More or faster procs put more contention on the data, so getting more or
   better cpus just increases the need for faster disks or more ram.

- PG is 64 bit if you compile it to be so, or if you install a 64-bit
   binary package.

....and all that said, application and schema design can play a far more
important role in performance than hardware.


On Wed, 31 Oct 2007, Ketema Harris wrote:

> I am trying to build a very Robust DB server that will support 1000+
> concurrent users (all ready have seen max of 237 no pooling being used).  i
> have read so many articles now that I am just saturated.  I have a general
> idea but would like feedback from others.
>
> I understand query tuning and table design play a large role in performance,
> but taking that factor away
> and focusing on just hardware, what is the best hardware to get for Pg to
> work at the highest level
> (meaning speed at returning results)?
>
> How does pg utilize multiple processors?  The more the better?
> Are queries spread across multiple processors?
> Is Pg 64 bit?
> If so what processors are recommended?
>
> I read this :
> http://www.postgresql.org/files/documentation/books/aw_pgsql/hw_performance/node12.html
> POSTGRESQL uses a multi-process model, meaning each database connection has
> its own Unix process. Because of this, all multi-cpu operating systems can
> spread multiple database connections among the available CPUs. However, if
> only a single database connection is active, it can only use one CPU.
> POSTGRESQL does not use multi-threading to allow a single process to use
> multiple CPUs.
>
> Its pretty old (2003) but is it still accurate?  if this statement is
> accurate how would it affect connection pooling software like pg_pool?
>
> RAM?  The more the merrier right? Understanding shmmax and the pg config file
> parameters for shared mem has to be adjusted to use it.
> Disks?  standard Raid rules right?  1 for safety 5 for best mix of
> performance and safety?
> Any preference of SCSI over SATA? What about using a High speed (fibre
> channel) mass storage device?
>
> Who has built the biggest baddest Pg server out there and what do you use?
>
> Thanks!
>
>
>
>
>
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