Re: SSD options, small database, ZFS - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: SSD options, small database, ZFS
Date
Msg-id 201111221810.pAMIATK15156@momjian.us
Whole thread Raw
In response to Re: SSD options, small database, ZFS  (Greg Smith <greg@2ndQuadrant.com>)
List pgsql-performance
Greg Smith wrote:
> The whole memorys speed topic is also much more complicated than any
> simple explanation can cover.  How many banks of RAM you can use
> effectively changes based on the number of CPUs and associated chipset
> too.  Someone just sent me an explanation recently of why I was seeing
> some strange things on my stream-scaling benchmark program.  That dove
> into a bunch of trivia around how the RAM is actually accessed on the
> motherboard.  One of the reasons I keep so many samples on that
> program's page is to help people navigate this whole maze, and have some
> data points to set expectations against.  See
> https://github.com/gregs1104/stream-scaling for the code and the samples.

I can confirm that a Xeon E5620 CPU wants memory to be in multiples of
3, and a dual-CPU 5620 system needs memory in multiples of 6.  (I
installed 12 2GB modules.)

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +

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