RE: Re: [ot] one for the networking guru's

["Jon Whiten" <jon@xxxxxxx>]

Unless i'm wrong, it looks as if there is a mixing up of bits and bytes
here.  Is a 100mb(it) ethernet connection only capable of around 5Mb(ytes)
per second transfer [100Mbit/s is of the order 10Mbyte/s less any further
framing overheads etc.].  Therefore to achieve 50Mbytes a 1Gig connection
would be required.

Regards,

Jon
http://www.whiten.co.uk/



> -----Original Message-----
> From: Phil Harris [mailto:phil@xxxxxxx]
> Sent: 10 October 2003 10:10
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] Re: [ot] one for the networking guru's
>
>
>
> I'm with Paul on this one I have to say...
>
> ...I'm finding that running 10/100 switched is at times a complete
PITA o=
n
> my servers when I'm copying around 6 or 7 Gb files.
>
> Transfer speeds to/from good fast SCSI arrays can be pretty impressive
- =
I
> set one up a while ago with a mate who does a lot of contract database
> design work on a machine he has at home and we were getting
> sustained writes
> in excess of 50Mbytes/sec and reads in excess of 74Mbytes/sec using
(IIRC=
)
> HDTach using an Adaptec U160 SCSI RAID controller and striped array of
> 10,000 rpm SCSI drives. Yes, it's noisy as buggery and gives of a lot
of
> heat but the access times and transfer rates are stunning!
>
> Even on my DVD server I'm finding that the limiting factor for how
many
> movies can be played simultaneously is (at the moment) the 100Mbit
link t=
o
> the switch which is saturating first - I currently have a
> RocketRAID404 card
> configured as RAID 0 (striped) with 8 x ATA133 drives which don't
> appear to
> be getting hammered and the load on the server remains at less than
30%
> (according to Win2k Server Task Manager).
>
> If I could afford one I'd definitely look at a 24 x 10/100 + 2 x
Copper
> Gigabit switch...
>
> Phil
>
> > -----Original Message-----
> > From: yhkeppy [mailto:keith@xxxxxxx]
> > Sent: 10 October 2003 09:00
> > To: ukha_d@xxxxxxx
> > Subject: [ukha_d] Re: [ot] one for the networking guru's
> >
> >
> > Paul,
> >
> > Try running a test yourself rather than relying on the manuf's
> > numbers (though if you have this type of setup i doubt you'll
find
> > any book details). Use perfmon - i'd be interested in hearing the
> > results (i normally work with large disk installations in SAN and
> > DAS setups, so i'd be interested in seeing how your system
measures
> > up).
> >
> > Keith
> >
> > --- In ukha_d@xxxxxxx, "Paul Gale" <groups@s...>
wrote:
> > >
> > > Ah, but I'm not talking about any old SCSI HDD's - I have a
> > striped array of ultra fast SCSI LVD 160 HDD's - this is a
> > requirement of my top end video edit station that can play THREE
> > streams of D1 digital video SIMULTANEOUSLY in an edit!!! :)
> > >
> > > I'll need to check the max performance as I can't remember
the
> > speeds - but it's way over 20MB per sec.
> > >
> > > Paul.
> > >
> > >
> > > -----Original Message-----
> > > From: yhkeppy [mailto:keith@xxxxxxx...]
> > > Sent: 09 October 2003 18:27
> > > To: ukha_d@xxxxxxx
> > > Subject: [ukha_d] Re: [ot] one for the networking guru's
> > >
> > > I agree with this. I'd also add that 100Mbps is actually
quite
> > fast
> > > in comparison with current disk transfer rates. When you
consider
> > > that a really fast ATA100 disk can write sustained at around
> > 35MB/s
> > > (which really is disk to disk across the disk bus on the
same
> > > machine with no CPU intervention), when you then have to get
that
> > > read/write cycle across the disk bus and out onto the comms
bus
> > when
> > > its not sustained either, that's going to go much over
15-20MB/s -
> > > and this is almost the same speed as a maxed out 100Mbps
network!!
> > >
> > > Sure gigabit network will remove A bottleneck, but I doubt
it will
> > > be the killer in your scenario. You could put second 100Mbps
cards
> > > into the machines, cross connect them and subnet them off.
> > Assuming
> > > they are also not connected together via a second network,
you
> > will
> > > avoid routing loops and you should theoretically get the
maximum
> > > efficiency out of the link.
> > >
> > > By the way, SATA and SCSI are actually not a lot faster than
> > modern
> > > IDE - the latest IDE drives are right up there on
performance, and
> > > SATA only improves this by a smallish margin. The real
difference
> > is
> > > in big storage architectures, where you can just have more
SATA or
> > > SCSI disk in a single store.
> > >
> > > Keith
> > >
> > > --- In ukha_d@xxxxxxx, "Shaf Ali"
<shaf@s...> wrote:
> > > > Mate be4 even considering this what is your current
throughput ?
> > > Where are
> > > > the bottlenecks ?
> > > >
> > > > I might be an idea to nail out your bottlenecks before
> > > proceeding...
> > > >
> > > > An example : Is 1 minute to transfer a 700Meg DivX file
not fast
> > > enough ?
> > > > Why am I not transfering this fast already ?
> > > >
> > > > Think of the software a nd architecture first.
> > > >
> > > > Shaf
> > > >
> > > >
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "Paul Gale" <groups@s...>
> > > > To: <ukha_d@xxxxxxx>
> > > > Sent: Thursday, October 09, 2003 4:16 PM
> > > > Subject: [ukha_d] [ot] one for the networking guru's
> > > >
> > > >
> > > > Got a few PC's connected via 100Mbps LAN - want to
connect two
> > of
> > > my edit PC
> > > > 's together via Gigabit networking to share very large
video and
> > > audio files
> > > > for edit. Can I add a second Ethernet card (gigabit) to
each so
> > > that peer to
> > > > peer traffic between them uses the faster link (they
both have
> > > very fast
> > > > disk IO - SCSI and SATA) and not the existing n/w
infrastructure?
> > > >
> > > > I guess this is a routing issue but how do you tell XP
and W2K
> > to
> > > do this?
> > > >
> > > > Cheers,
> > > >
> > > > Paul.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > UKHA 2004: 15th and 16th May 2004
> > > >
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