Re: random_page_costs - are defaults of 4.0 realistic for SCSI RAID 1 - Mailing list pgsql-performance

"Decibel!" <decibel@decibel.org> writes:

> On Tue, Sep 11, 2007 at 02:49:28PM -0400, Jean-David Beyer wrote:
>> It is tricky for me to find a big enough file to test. I tried one of the
>
> dd if=/dev/zero of=bigfile bs=8192 count=1000000

On linux another useful trick is:

echo 1 > /proc/sys/vm/drop_caches

Also, it helps to run a "vmstat 1" in another window and watch the bi and bo
columns.

--
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com