Re: Intel SRCS16 SATA raid? - Mailing list pgsql-performance

Nice research Alex.

Your data strongly support the information in the paper.  Your SCSI drives
blew away the others in all of the server benchmarks.  They're only
marginally better in desktop use.

I do find it somewhat amazing that a 15K SCSI 320 drive isn't going to help
me play Unreal Tournament much faster.  That's okay.  I suck at it anyway.
My kid has never lost to me.  She enjoys seeing daddy as a bloody smear and
bouncing body parts anyway.  It promotes togetherness.

Here's a quote from the paper:

"[SCSI] interfaces support multiple initiators or hosts. The
drive must keep track of separate sets of information for each
host to which it is attached, e.g., maintaining the processor
pointer sets for multiple initiators and tagged commands.
The capability of SCSI/FC to efficiently process commands
and tasks in parallel has also resulted in a higher overhead
“kernel” structure for the firmware."

Has anyone ever seen a system with multiple hosts or initiators on a SCSI
bus?  Seems like it would be a very cool thing in an SMP architecture, but
I've not seen an example implemented.

Rick

Alex Turner <armtuk@gmail.com> wrote on 04/14/2005 12:13:41 PM:

> I have put together a little head to head performance of a 15k SCSI,
> 10k SCSI 10K SATA w/TCQ, 10K SATA wo/TCQ and 7.2K SATA drive
> comparison at storage review
>
> http://www.storagereview.com/php/benchmark/compare_rtg_2001.php?
>

typeID=10&testbedID=3&osID=4&raidconfigID=1&numDrives=1&devID_0=232&devID_1=40&devID_2=259&devID_3=267&devID_4=261&devID_5=248&devCnt=6

>
> It does illustrate some of the weaknesses of SATA drives, but all in
> all the Raptor drives put on a good show.
>
> Alex Turner
> netEconomist
>
> On 4/14/05, Alex Turner <armtuk@gmail.com> wrote:
> > I have read a large chunk of this, and I would highly recommend it to
> > anyone who has been participating in the drive discussions.  It is
> > most informative!!
> >
> > Alex Turner
> > netEconomist
> >
> > On 4/14/05, Richard_D_Levine@raytheon.com
> <Richard_D_Levine@raytheon.com> wrote:
> > > Greg,
> > >
> > > I posted this link under a different thread (the $7k server
> thread).  It is
> > > a very good read on why SCSI is better for servers than ATA.  I
> didn't note
> > > bias, though it is from a drive manufacturer.  YMMV.  There is an
> > > interesting, though dated appendix on different manufacturers' drive
> > > characteristics.
> > >
> > > http://www.seagate.
>
com/content/docs/pdf/whitepaper/D2c_More_than_Interface_ATA_vs_SCSI_042003.pdf

> > >
> > > Enjoy,
> > >
> > > Rick
> > >
> > > pgsql-performance-owner@postgresql.org wrote on 04/14/2005 09:54:45
AM:
> > >
> > > >
> > > > Our vendor is trying to sell us on an Intel SRCS16 SATA raid
controller
> > > > instead of the 3ware one.
> > > >
> > > > Poking around it seems this does come with Linux drivers and there
is a
> > > > battery backup option. So it doesn't seem to be completely insane.
> > > >
> > > > Anyone have any experience with these controllers?
> > > >
> > > > I'm also wondering about whether I'm better off with one of these
SATA
> > > raid
> > > > controllers or just going with SCSI drives.
> > > >
> > > > --
> > > > greg
> > > >
> > > >
> > > > ---------------------------(end of
broadcast)---------------------------
> > > > TIP 8: explain analyze is your friend
> > >
> > > ---------------------------(end of
broadcast)---------------------------
> > > TIP 9: the planner will ignore your desire to choose an index scan if
your
> > >       joining column's datatypes do not match
> > >
> >