Re: Advice sought : new database server - Mailing list pgsql-performance

On 04/03/12, Scott Marlowe (scott.marlowe@gmail.com) wrote:
> On Sun, Mar 4, 2012 at 2:58 AM, Rory Campbell-Lange
> <rory@campbell-lange.net> wrote:

> > [About existing server...] We would get faster performance, I
> > believe, by providing more RAM. Sorry -- I should have some pg_bench
> > output to share here.
>
> RAM is always a good thing, and it's cheap enough that you can throw
> 32 or 64G at a machine like this pretty cheaply.

Thanks for your note.

> >    1U chassis with 8 2.5" disk bays
> >    2x Intel Xeon E5630 Quad-Core / 4x 2.53GHz / 12MB cache
> >    8 channel Areca ARC-1880i (PCI Express x8 card)
> >      presumably with BBU (can't see it listed at present)
> >    2 x 300GB SAS  2.5" disks for operating system
> >      (Possibly also 300GB SATA VelociRaptor/10K RPM/32MB cache
> >      RAID 1
> >    4 x 300GB SAS  2.5" storage disks
> >      RAID 10
> >    48.0GB DDR3 1333MHz registered ECC (12x 4.0GB modules)
> >
> > My major question about this chassis, which is 1U, is that it only takes
> > 2.5" disks, and presently the supplier does not show 15K SAS disk
> > options. Assuming that I can get the BBU for the Areca card, and that
> > 15K SAS disks are available, I'd be grateful for comments on this
> > configuration.
>
> The 15k RPM disks aren't that big of a deal unless you're pushing the
> bleeding edge on a transactional system. I'm gonna take a wild guess
> that you're not doing heavy transactions, in which case, the BBU on
> the areca is the single most important thing for you to get for good
> performance.  The areca 1880 is a great controller and is much much
> easier to configure than the LSI.  Performance wise it's one of the
> fastest DAS controllers made.

We do have complex transactions, but I haven't benchmarked the
performance so I can't describe it. Few of the databases are at the many
million row size at the moment, and we are moving to an agressive scheme
of archiving old data, so we hope to keep things fast.

However I thought 15k disks were a pre-requisite for a fast database
system, if one can afford them? I assume if all else is equal the 1880
controller will run 20-40% faster with 15k disks in a write-heavy
application. Also I would be grateful to learn if there is a good reason
not to use 2.5" SATA disks.

> If the guys you're looking at getting this from can't do custom
> orders, find a white box dealer who can, like www.aberdeeninc.com.  It
> might not be on their site, but they can build dang near anything you
> want.

Thanks for the note about Aberdeen. I've seen the advertisements, but
not tried them yet.

Thanks for your comments
Rory

--
Rory Campbell-Lange
rory@campbell-lange.net

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