Re: sustained update load of 1-2k/sec

From: Ron
Subject: Re: sustained update load of 1-2k/sec
Date: ,
Msg-id: 6.2.3.4.0.20050819124201.05c15e40@pop.earthlink.net
(view: Whole thread, Raw)
In response to: Re: sustained update load of 1-2k/sec  ("Jeffrey W. Baker")
List: pgsql-performance

Tree view

sustained update load of 1-2k/sec  (Mark Cotner, )
 Re: sustained update load of 1-2k/sec  (Bob Ippolito, )
  Re: sustained update load of 1-2k/sec  (Mark Cotner, )
   Re: sustained update load of 1-2k/sec  (Bob Ippolito, )
  Re: sustained update load of 1-2k/sec  (Tom Lane, )
   Re: sustained update load of 1-2k/sec  (Andreas Pflug, )
    Re: sustained update load of 1-2k/sec  (Tom Lane, )
    Re: sustained update load of 1-2k/sec  (Ron, )
   Re: sustained update load of 1-2k/sec  (PFC, )
    Re: sustained update load of 1-2k/sec  (Mark Cotner, )
 Re: sustained update load of 1-2k/sec  (Alex Turner, )
  Re: sustained update load of 1-2k/sec  (Ron, )
   Re: sustained update load of 1-2k/sec  ("Jeffrey W. Baker", )
    Re: sustained update load of 1-2k/sec  (Ron, )
   Re: sustained update load of 1-2k/sec  (Alex Turner, )
    Re: sustained update load of 1-2k/sec  (Ron, )
 Re: sustained update load of 1-2k/sec  ("J. Andrew Rogers", )
  Re: sustained update load of 1-2k/sec  (Mark Cotner, )

At 12:34 PM 8/19/2005, Jeffrey W. Baker wrote:
>On Fri, 2005-08-19 at 10:54 -0400, Ron wrote:
> > Maxtor Atlas 15K II's.
>
> > Areca's 1GB buffer RAID cards
>
>The former are SCSI disks and the latter is an SATA controller.  The
>combination would have a transaction rate of approximately 0.

You are evidently thinking of the Areca ARC-11xx controllers (and you
are certainly right for that HW combination ;-) ).  Those are not the
only product Areca makes that can be upgraded to a 1GB cache.

Until SAS infrastructure is good enough, U320 SCSI and FC HD's remain
the top performing HD's realistically available.  At the most
fundamental, your DBMS is only as good as your HD IO subsystem, and
your HD IO subsystem is only as good as your HDs.  As others have
said here, skimping on your HDs is _not_ a good design choice where
DBMSs are concerned.

As an aside, the Atlas 15K II's are now available in SAS:

http://www.maxtor.com/portal/site/Maxtor/menuitem.ba88f6d7cf664718376049b291346068/?channelpath=/en_us/Products/SCSI%20Hard%20Drives/Atlas%2015K%20Family/Atlas%2015K%20II%20SAS

I haven't seen independent benches on them, so I explicitly
referenced the U320 Atlas 15K II's known performance numbers
instead.  As I said, Maxtor is claiming even better for the SAS
version of the Atlas 15K II.

None of the SAS <-> PCI-X or PCI-E RAID cards I know of are ready for
mass market yet, although a few are in beta..


>I can vouch for the Areca controllers, however.  You can certainly
>achieve pgbench transaction rates in the hundreds per second even with
>only 5 7200RPM disks and 128MB cache.
>
>Don't forget to buy the battery.

Agreed.

Hope this is helpful,
Ron Peacetree




pgsql-performance by date:

From: Mark Cotner
Date:
Subject: Re: sustained update load of 1-2k/sec
From: Dan Harris
Date:
Subject: Re: Query plan looks OK, but slow I/O - settings advice?