I have an Asus A8N-SLI Deluxe motherboard, and I want to create
3TB of, let's call it temporary space, on a single NTFS partition.
(By temporary, I mean the contents are replaceable from the source
data in the event of a disk crash, and the source data is safely
backed up; so RAID-0 will suffice.)
I already have two PATA and four SATA 500GB hard disks, and the
NVRAID controller built into the motherboard allows an array to
span both PATA and SATA disks. I'd rather not spend hundreds of
pounds on four new 750GB hard disks, when what I already have
will do.
I know there's a noticeable speed advantage in putting the PATA
hard drives on separate IDE channels. Also, the NVRAID controller
does support SATA-2, despite the manual's claim to the contrary.
Would it make any difference if I connect the PATA drives as
third and sixth in the array, rather than fifth and sixth?
I'm wondering if it would help to spread out the accesses to
the relatively slow UDMA-100 controllers, rather than going
to the second one immediately after the first one.
The computer also has a DVD writer that I hardly ever use.
Would there be any harm in leaving it attached as a slave
drive, on one of the PATA channels to be used by the RAID?
In comp.sys.ibm.pc.hardware.storage A. J. Moss <ajmoss_throwaway_account_001@hotmail.co.uk> wrote:
> I have an Asus A8N-SLI Deluxe motherboard, and I want to create
> 3TB of, let's call it temporary space, on a single NTFS partition.
> (By temporary, I mean the contents are replaceable from the source
> data in the event of a disk crash, and the source data is safely
> backed up; so RAID-0 will suffice.)
> I already have two PATA and four SATA 500GB hard disks, and the
> NVRAID controller built into the motherboard allows an array to
> span both PATA and SATA disks. I'd rather not spend hundreds of
> pounds on four new 750GB hard disks, when what I already have
> will do.
> I know there's a noticeable speed advantage in putting the PATA
> hard drives on separate IDE channels. Also, the NVRAID controller
> does support SATA-2, despite the manual's claim to the contrary.
> Would it make any difference if I connect the PATA drives as
> third and sixth in the array, rather than fifth and sixth?
The difference should not be too large, since you use
SPAN/JBOD/APPEND mode. It switches between disks only seldomly.
> I'm wondering if it would help to spread out the accesses to
> the relatively slow UDMA-100 controllers, rather than going
> to the second one immediately after the first one.
Since when is UDMA-100 slow?
> The computer also has a DVD writer that I hardly ever use.
> Would there be any harm in leaving it attached as a slave
> drive, on one of the PATA channels to be used by the RAID?
On Sun, 29 Jul 2007 07:06:59 -0700, "A. J. Moss"
<ajmoss_throwaway_account_001@hotmail.co.uk> wrote:
>I have an Asus A8N-SLI Deluxe motherboard, and I want to create
>3TB of, let's call it temporary space, on a single NTFS partition.
>(By temporary, I mean the contents are replaceable from the source
>data in the event of a disk crash, and the source data is safely
>backed up; so RAID-0 will suffice.)
>
>I already have two PATA and four SATA 500GB hard disks, and the
>NVRAID controller built into the motherboard allows an array to
>span both PATA and SATA disks. I'd rather not spend hundreds of
>pounds on four new 750GB hard disks, when what I already have
>will do.
>
>I know there's a noticeable speed advantage in putting the PATA
>hard drives on separate IDE channels.
All good.
>Also, the NVRAID controller
>does support SATA-2, despite the manual's claim to the contrary.
Not that that matters much.
>Would it make any difference if I connect the PATA drives as
>third and sixth in the array, rather than fifth and sixth?
>I'm wondering if it would help to spread out the accesses to
>the relatively slow UDMA-100 controllers, rather than going
>to the second one immediately after the first one.
I'd be surprised if it did make any difference. To a first-order
approximation, UDMA-100 supports up to 100meg/second bandwidth; each
hard drive will actually support maybe 40-60meg/second. With only a
single hard drive on each IDE ribbon, you're well within bandwidth.
The limiting factor with a six-disk RAID0 system is more likely to be
your motherboard bus. The manual doesn't include a block diagram of
how the components are connected, so it's possible that the RAID chip
is on the end of a lovely slow PCI bus...
On the other hand, it's the work of half an hour to try it each way
and benchmark - just don't try and format a whole 3Tb partition each
time! A 10gig or so partition will suffice for this particular test.
>The computer also has a DVD writer that I hardly ever use.
>Would there be any harm in leaving it attached as a slave
>drive, on one of the PATA channels to be used by the RAID?
No, that's fine - UDMA devices don't slow the bus when they're not in
use.
Jaimie Vandenbergh wrote:
> On Sun, 29 Jul 2007 07:06:59 -0700, "A. J. Moss"
> <ajmoss_throwaway_account_001@hotmail.co.uk> wrote:
>
>>Would it make any difference if I connect the PATA drives as
>>third and sixth in the array, rather than fifth and sixth?
>>I'm wondering if it would help to spread out the accesses to
>>the relatively slow UDMA-100 controllers, rather than going
>>to the second one immediately after the first one.
>
> I'd be surprised if it did make any difference. To a first-order
> approximation, UDMA-100 supports up to 100meg/second bandwidth; each
> hard drive will actually support maybe 40-60meg/second. With only a
> single hard drive on each IDE ribbon, you're well within bandwidth.
IIRC, UDMA maxes out at about 75% of theoretical transfer rate, so for a
modern drive with up to 90MB/s sequential transfer, it's marginal.
That's not going to matter much here, because even if a single drive is
limited to 75MB/s, that's going to be 450MB/s for the whole array.
Regardless, that's not actually the issue here. The question is whether
the two UDMA controllers share a limited bus, separately from the SATA
controllers. I can't decide whether this is likely or not.
> The limiting factor with a six-disk RAID0 system is more likely to be
> your motherboard bus. The manual doesn't include a block diagram of
> how the components are connected, so it's possible that the RAID chip
> is on the end of a lovely slow PCI bus...
It's a southbridge-integrated controller, so it's not going to be PCI.
Still, it's quite possible that there's a bus somewhere along the line
that can't handle 500MB/sec.
"Arno Wagner" <me@privacy.net> wrote in message news:5h3ueqF3iifbkU2@mid.individual.net
> In comp.sys.ibm.pc.hardware.storage A. J. Moss <ajmoss_throwaway_account_001@hotmail.co.uk> wrote:
> > I have an Asus A8N-SLI Deluxe motherboard, and I want to create
> > 3TB of, let's call it temporary space, on a single NTFS partition.
> > (By temporary, I mean the contents are replaceable from the source
> > data in the event of a disk crash, and the source data is safely
> > backed up; so RAID-0 will suffice.)
>
> > I already have two PATA and four SATA 500GB hard disks, and the
> > NVRAID controller built into the motherboard allows an array to
> > span both PATA and SATA disks. I'd rather not spend hundreds of
> > pounds on four new 750GB hard disks, when what I already have will do.
>
> > I know there's a noticeable speed advantage in putting the PATA
> > hard drives on separate IDE channels. Also, the NVRAID controller
> > does support SATA-2, despite the manual's claim to the contrary.
>
> > Would it make any difference if I connect the PATA drives as
> > third and sixth in the array, rather than fifth and sixth?
>
> The difference should not be too large, since you use
> SPAN/JBOD/APPEND mode. It switches between disks only seldomly.
Babblehead, what exactly did you not understand in "Optimising speed of RAID-0 (mixed SATA/PATA)"?
>
> > I'm wondering if it would help to spread out the accesses to
> > the relatively slow UDMA-100 controllers, rather than going
> > to the second one immediately after the first one.
>
> Since when is UDMA-100 slow?
>
> > The computer also has a DVD writer that I hardly ever use.
> > Would there be any harm in leaving it attached as a slave
> > drive, on one of the PATA channels to be used by the RAID?
>
> If it is inactive, it should not matter.
>
> Arno
"Jaimie Vandenbergh" <jaimie@sometimes.sessile.org> wrote in message news:fcgpa31jsdne8i1hhdoavrjg4dpqg566h1@newspostin g.sessile.org
> On Sun, 29 Jul 2007 07:06:59 -0700, "A. J. Moss"
> <ajmoss_throwaway_account_001@hotmail.co.uk> wrote:
>
> > I have an Asus A8N-SLI Deluxe motherboard, and I want to create
> > 3TB of, let's call it temporary space, on a single NTFS partition.
> > (By temporary, I mean the contents are replaceable from the source
> > data in the event of a disk crash, and the source data is safely
> > backed up; so RAID-0 will suffice.)
> >
> > I already have two PATA and four SATA 500GB hard disks, and the
> > NVRAID controller built into the motherboard allows an array to
> > span both PATA and SATA disks. I'd rather not spend hundreds of
> > pounds on four new 750GB hard disks, when what I already have
> > will do.
> >
> > I know there's a noticeable speed advantage in putting the PATA
> > hard drives on separate IDE channels.
>
> All good.
>
> > Also, the NVRAID controller
> > does support SATA-2, despite the manual's claim to the contrary.
>
> Not that that matters much.
>
> > Would it make any difference if I connect the PATA drives as
> > third and sixth in the array, rather than fifth and sixth?
> > I'm wondering if it would help to spread out the accesses to
> > the relatively slow UDMA-100 controllers, rather than going
> > to the second one immediately after the first one.
They're going out in parallel anyway if on seperate channels.
>
> I'd be surprised if it did make any difference. To a first-order approxi
> mation, UDMA-100 supports up to 100meg/second bandwidth; each hard
> drive will actually support maybe 40-60meg/second. With only a
> single hard drive on each IDE ribbon, you're well within bandwidth.
He probably meant 'access time' or latency', not transfer speed.
>
> The limiting factor with a six-disk RAID0 system is more likely to be
> your motherboard bus. The manual doesn't include a block diagram of
> how the components are connected, so it's possible that the RAID chip
> is on the end of a lovely slow PCI bus...
>
> On the other hand, it's the work of half an hour to try it each way
> and benchmark - just don't try and format a whole 3Tb partition each
> time! A 10gig or so partition will suffice for this particular test.
A Format speed test, what else is new.
>
> > The computer also has a DVD writer that I hardly ever use.
> > Would there be any harm in leaving it attached as a slave
> > drive, on one of the PATA channels to be used by the RAID?
> No, that's fine - UDMA devices don't slow the bus when they're not in use.
Right, so make sure it is in UDMA mode or replace with an UDMA model. Idjut.
"John Jordan" <junk@jaj22.org.uk> wrote in message news:5h4an9F3gc8ooU1@mid.individual.net
> Jaimie Vandenbergh wrote:
> > On Sun, 29 Jul 2007 07:06:59 -0700, "A. J. Moss" <ajmoss_throwaway_account_001@hotmail.co.uk> wrote:
> >
> > > Would it make any difference if I connect the PATA drives
> > > as third and sixth in the array, rather than fifth and sixth?
> > > I'm wondering if it would help to spread out the accesses to
> > > the relatively slow UDMA-100 controllers, rather than going
> > > to the second one immediately after the first one.
> >
> > I'd be surprised if it did make any difference. To a first-order appro-
> > ximation, UDMA-100 supports up to 100meg/second bandwidth; each
> > hard drive will actually support maybe 40-60meg/second. With only a
> > single hard drive on each IDE ribbon, you're well within bandwidth.
> IIRC, UDMA maxes out at about 75% of theoretical transfer rate,
There is no such 'theoretical' transfer rate.
There is about 10% command overhead in IDE when using DMA bus protocol.
> so for a modern drive with up to 90MB/s sequential transfer,
90 eh? No kidding.
> it's marginal.
Actually, that should suffice.
> That's not going to matter much here, because even if a single drive is
> limited to 75MB/s, that's going to be 450MB/s for the whole array.
>
> Regardless, that's not actually the issue here. The question is whether
> the two UDMA controllers
You mean the IDE controllers.
> share a limited bus,
Of course they do.
> separately from the SATA controllers.
> I can't decide whether this is likely or not.
>
> > The limiting factor with a six-disk RAID0 system is more likely to be
> > your motherboard bus. The manual doesn't include a block diagram of
> > how the components are connected, so it's possible that the RAID chip
> > is on the end of a lovely slow PCI bus...
> It's a southbridge-integrated controller,
> so it's not going to be PCI.
Uhuh, and this has what exactly to do with "being on the southbridge"?
And *what* southbridge, it's single chip.
> Still, it's quite possible that there's a bus somewhere along the line
> that can't handle 500MB/sec.
Cheers - Jaimie
--
"We've heard that a million monkeys at a million keyboards could produce
the Complete Works of Shakespeare. Now, thanks to the Internet, we know
this is not true." - Robert Wilensky, University of California
Folkert Rienstra wrote:
> "John Jordan" <junk@jaj22.org.uk> wrote in message news:5h4an9F3gc8ooU1@mid.individual.net
>
>>IIRC, UDMA maxes out at about 75% of theoretical transfer rate,
>
> There is no such 'theoretical' transfer rate.
> There is about 10% command overhead in IDE when using DMA bus protocol.
"Theoretical" was a poor choice of words. However, I just tested burst
rates with HD Tune on a few different drives and a board that can limit
UDMA rates in the BIOS, and I don't get anything like a flat 10%:
The UDMA-6 result may be limited by drive electronics, but the others
suggest that the overhead increases with transfer rate.
>>so for a modern drive with up to 90MB/s sequential transfer,
>
> 90 eh? No kidding.
I don't know if I'm reading your sarcasm correctly, but many recent SATA
drives do touch 90MB/s. The IDE drives may be slower, but it's hard to
tell because no-one reviews them.
>>Still, it's quite possible that there's a bus somewhere along the line
>>that can't handle 500MB/sec.
>
> It has Hypertransport, 800MB/s.
Hypertransport is 1.6GB/s or more likely 2GB/s each way on that board. I
was referring more to internal buses in the chipset, although it's
possible that the HT or memory bus performs poorly on DMA transfers.
"John Jordan" <junk@jaj22.org.uk> wrote in message news:5h7d2fF3k4g4gU1@mid.individual.net
> Folkert Rienstra wrote:
> > "John Jordan" <junk@jaj22.org.uk> wrote in message news:5h4an9F3gc8ooU1@mid.individual.net
> >
> > > IIRC, UDMA maxes out at about 75% of theoretical transfer rate,
> >
> > There is no such 'theoretical' transfer rate.
> > There is about 10% command overhead in IDE when using DMA bus protocol.
>
> "Theoretical" was a poor choice of words. However, I just tested burst
> rates with HD Tune on a few different drives and a board that can limit
> UDMA rates in the BIOS, and I don't get anything like a flat 10%:
>
> UDMA-6 (133): 95MB/s
> UDMA-5 (100): 76-78MB/s
> UDMA-4 (66): 55-56MB/s
> UDMA-3 (44): 35-38MB/s
> UDMA-2 (33): 30MB/s
Burst rates are unreliable, they depend on drive caching behaviour.
Use STR. What does HD Tach say.
>
> The UDMA-6 result may be limited by drive electronics, but the others
> suggest that the overhead increases with transfer rate.
>
> > > so for a modern drive with up to 90MB/s sequential transfer,
> >
> > 90 eh? No kidding.
>
> I don't know if I'm reading your sarcasm correctly, but many recent SATA
> drives do touch 90MB/s.
Many even.
The Hitachi 7K1000 comes close though, so does the new WD Raptor but that's a 10k drive.
Seagate Barracudas are relatively slow apparently at 75, 78 for the ES
and not the norm.
WD's new Caviar beats everything handsdown though at a staggering 97MB/s.
So you are correct, drive speeds have finally stepped up very recently.
Storage Review are lagging quite a bit behind with their bench-
mark database, depending on which one you pick. That's my fault.
> The IDE drives may be slower, but it's hard to tell because no-one reviews them.
>
> > > Still, it's quite possible that there's a bus somewhere along the line
> > > that can't handle 500MB/sec.
> >
> > It has Hypertransport, 800MB/s.
> Hypertransport is 1.6GB/s or more likely 2GB/s each way on that board.
Optimising speed of RAID-0 (mixed SATA/PATA) 
Linear Mode
