Re: PostgreSQL in virtual machine - Mailing list pgsql-performance

From Harald Armin Massa
Subject Re: PostgreSQL in virtual machine
Date
Msg-id 7be3f35d0703120800kc3bbb99ub818fca7322ed161@mail.gmail.com
Whole thread Raw
In response to PostgreSQL in virtual machine  (Andreas Tille <tillea@rki.de>)
List pgsql-performance
Andreas,

I am responsible for some active PostgreSQL databases within virtual
machines and on "plain metal"; all using Windows.

There are spurious strange performance issues on those PostreSQL
databases within the virtual machines. I can not pin them down (yet),
and am not really able to blame them on vmware; but just want to
recommend to be very very carefull about PostgreSQL in vmware and
please communcate your findings.

> from a PostgreSQL 8.1 database in a virtual machine.  I'm able to
> adjust the memory of this machine according to reasonable values
> and can choose between one or two (emulated) processors.  The
> question is: How can I find an optimal relation between the
> virtual hardware parameters and PostgreSQL performance.  I guess

You did not specify the OS in your VM. I can report my experiences
with W2k3 inside the VM:

contrary to usual recommendations, smaller shared_buffers yielded
better results.
Growing effective_cache_size yielded the best results for me.


Harald



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