Date: Fri, 03 Aug 2001 03:56:44 -0700 From: Mike Smith <msmith@freebsd.org> To: Joerg Micheel <joerg@cs.waikato.ac.nz> Cc: Mike Smith <msmith@freebsd.org>, "Jose M. Alcaide" <jose@we.lc.ehu.es>, hardware@freebsd.org Subject: Re: 3ware Escalade 7xxx supported? Message-ID: <200108031056.f73AuiB00834@mass.dis.org> In-Reply-To: Your message of "Wed, 01 Aug 2001 09:08:29 %2B1200." <20010801090829.B17381@cs.waikato.ac.nz>
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> On Tue, Jul 31, 2001 at 12:55:43AM -0700, Mike Smith wrote:
> > > I did a simple read performance test (dd if=/dev/twed0 of=/dev/null bs=64
> k)
> > > and I got about 55 MB/s. Hey, that's good :-)
> >
> > Yes. 8)
>
> What do people do if they need 60, 90 or 120 MByte/sec throughput ?
> I have done some experiments with SCSI and there appears to be a
> cap around 80 MByte/sec, regardless how many disks or controllers
> are involved (not a strict FreeBSD problem, only).
Typically, you go wider and faster. A lot of controllers don't have the
internal memory bandwidth to do more than about 80 or so; they are OK or
even good at maximising the performance of their disks up to that point,
but run out of puff beyond it.
Intel recently released a new I/O chipset based on a very fast (733MHz)
StrongArm core; it has two 64/66MHz PCI bridges and a decent memory
interface. I'd guess that we'll see controllers using this appearing in
a year or so, and based on the numbers I ran on this part a while back,
they ought to be able to sustain something around 300MB/sec out of it.
This is all vapour of course; I am only guessing that these parts will
hit the mainstream RAID controller market.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
V I C T O R Y N O T V E N G E A N C E
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