Re: Best OS & Configuration for Dual Xeon w/4GB & - Mailing list pgsql-performance

From Jim C. Nasby
Subject Re: Best OS & Configuration for Dual Xeon w/4GB &
Date
Msg-id 20060320144503.GR15742@pervasive.com
Whole thread Raw
In response to Re: Best OS & Configuration for Dual Xeon w/4GB &  (Scott Marlowe <smarlowe@g2switchworks.com>)
Responses Re: Best OS & Configuration for Dual Xeon w/4GB &
Re: Best OS & Configuration for Dual Xeon w/4GB &
List pgsql-performance
On Fri, Mar 17, 2006 at 05:00:34PM -0600, Scott Marlowe wrote:
> > last pid:  5788;  load averages:  0.32,  0.31,  0.28                                                     up
127+15:16:0813:59:24 
> > 169 processes: 1 running, 168 sleeping
> > CPU states:  5.4% user,  0.0% nice,  9.9% system,  0.0% interrupt, 84.7% idle
> > Mem: 181M Active, 2632M Inact, 329M Wired, 179M Cache, 199M Buf, 81M Free
> > Swap: 4096M Total, 216K Used, 4096M Free
> >
> >   PID USERNAME      PRI NICE  SIZE    RES STATE  C   TIME   WCPU    CPU COMMAND
> > 14501 pgsql           2   0   254M   242M select 2  76:26  1.95%  1.95% postgre
> >  5720 root           28   0  2164K  1360K CPU0   0   0:00  1.84%  0.88% top
> >  5785 pgsql           2   0   255M 29296K sbwait 0   0:00  3.00%  0.15% postgre
> >  5782 pgsql           2   0   255M 11900K sbwait 0   0:00  3.00%  0.15% postgre
> >  5772 pgsql           2   0   255M 11708K sbwait 2   0:00  1.54%  0.15% postgre
>
> That doesn't look good.  Is this machine freshly rebooted, or has it
> been running postgres for a while?  179M cache and 199M buffer with 2.6
> gig inactive is horrible for a machine running a 10gig databases.

No, this is perfectly fine. Inactive memory in FreeBSD isn't the same as
Free. It's the same as 'active' memory except that it's pages that
haven't been accessed in X amount of time (between 100 and 200 ms, I
think). When free memory starts getting low, FBSD will start moving
pages from the inactive queue to the free queue (possibly resulting in
writes to disk along the way).

IIRC, Cache is the directory cache, and Buf is disk buffers, which is
somewhat akin to shared_buffers in PostgreSQL.
--
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461

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