SCSI Hard Drives for Home comp ??

[Trimble Bracegirdle]

With my newly put together Home Computer ...games , general purpose use, C2D
E6600 @ 3.2 Gig, Geforce 8800 ...Win XP or VISTA.
I'm becoming increasingly aware of speed limitations with standard SATA2
hard drives I have.
looked at the Raptor Drives ...far to expensive for the little improvement
Re.
standard SATA2 .
I really don't like the prospect of RAID...I would need at least 2
identical drives with a reduction
in reliability (2 rather than 1 thing to go wrong) ...to get RAID speed
improvement with a
good level of error protection I would need SERIAL ATTACHED SCSI3 or more
drives ...all to complicated .

SOOO ! what about SCSI Hard drives ...I see Rpm's of 15000 ..access times
less than 1/2
that of standard SATA2 ..the only way it could into go in my system is
(presumably)
with a controller card into the standard PCI slots (33 MHz) ...does that
have the speed ??.
Orthough there is now something called 'SERIAL ATTACHED SCSI'

I don't seem to see this approached ever mentioned in connection to IBM PC
comp. Home computers
so I guess the answer is NO !!
Some one want to tell why ?
(\__/)
(='.'=)
(")_(") mouse

 

[Tim S]

With my newly put together Home Computer ...games , general purpose use,
C2D E6600 @ 3.2 Gig, Geforce 8800 ...Win XP or VISTA.
I'm becoming increasingly aware of speed limitations with standard SATA2
hard drives I have.
looked at the Raptor Drives ...far to expensive for the little improvement
Re.
standard SATA2 .
I really don't like the prospect of RAID...I would need at least 2
identical drives with a reduction
in reliability (2 rather than 1 thing to go wrong)

How about 4 cheap disks in a RAID0+1 configuration. Double the effective
transfer speed, plus redundancy. Probably still cheaper than top of the
line 15k RPM SCSI disks + controller.

Do it in software, no need for fancy cards for that.

Cheers

Tim

 

[HDRDTD]

You don't typically hear about home users using SCSI drives because of their
cost. Yes they are fast especially with the 15k rpm ultra 320 drives, but if
you consider the cost per capacity, you'll soon realize why they are
typically reserved for use in higher end workstations or servers.

If you're serious, consider the cost of a SCSI Raid adapter for your PC in
addition to the cost of the SCSI drives, which at the 15k rpm level come in
capacities far smaller that what's available in SATA drives these days for
the same cost.

For a home PC that you're describing as 'general purpose use', going to 15k
rpm SCSI is overkill unless you have plenty of money to throw at it for the
performance gain you would get.

If you think Raptors are expensive for the performance improvement you get,
wait till you get prices on 15K SCSI drives of the same capacity especially
considering that you need to add the cost of a good SCSI card.

If you want spped and safety, you can always consider a RAID 5 array or a
RAID 10 array.

 

[Guest]

It depends how one prioritizes. Personally I hate drive failures,
and have been running the same set of four Seagate 15K.3
drives for almost five years now. They're built like tanks, run
at 30C at load and are virtually silent. My Adaptec 39320
controller cost $60 from eBay.

 

[kony]

With my newly put together Home Computer ...games , general purpose use, C2D
E6600 @ 3.2 Gig, Geforce 8800 ...Win XP or VISTA.
I'm becoming increasingly aware of speed limitations with standard SATA2
hard drives I have.

Doing which tasks? Often, HDD speed is a secondary problem
to lack of system memory. Certainly not always.

looked at the Raptor Drives ...far to expensive for the little improvement
Re.
standard SATA2 .

What is it you are expecting, you can get a significant
performance increase without paying not only the base cost
of a drive but also the addt'l cost that higher performers
command?

A Raptor is one popular answer and rightly so because it has
lower latency, without the addt'l expense of SCSI and a SCSI
controller. You don't need substantially higher throughput
(MB/s) for your OS and "general purpose use", but you might
for certain tasks like simple manipulations (not compute
bound) of large, like video, files.

I really don't like the prospect of RAID...I would need at least 2
identical drives

No, they don't need to be identical. They need both run
under same interface supported by the controller (whether it
be PATA(nnn) or SATA, SCSI, and your array size is limited
based on the size of the smallest member (drive) in the
array. Somewhere some crazy nut years ago wrongly spread
the myth that RAID needs indentical drives and unfortunately
the myth was propigated by those who didn't read any more or
never tried it.

with a reduction
in reliability (2 rather than 1 thing to go wrong) ...to get RAID speed
improvement with a
good level of error protection I would need SERIAL ATTACHED SCSI3 or more
drives ...all to complicated .

Well yes it is an additional level of "complication", and
more expensive. Now you have the crux of why everyone isn't
doing it... but you seem to want MORE than what everyone
else has so... you are weighing same choices everyone else
did and picking one way or the other like everyone else.

SOOO ! what about SCSI Hard drives ...I see Rpm's of 15000 ..access times
less than 1/2
that of standard SATA2 ..the only way it could into go in my system is
(presumably)
with a controller card into the standard PCI slots (33 MHz) ...does that
have the speed ??.

It has low latency. One SCSI drive with added cost of a
controller is a poor value, particularly so on a 33MHz/32bit
PCI bus. Better to just get one Raptor, see if you find
that acceptible, then if you do not, get a second one and
RAID them.


Then again you may just have insufficient memory as I'd
stated initially. Without having larger filesets than will
fit in system memory cache, the system shouldn't be
continually having rereads from HDD. Going with Vista you
will exacerbate the problem, more and larger OS files means
more time to read them given same drive(s), unless of course
you had the files cached in system memory, which is what XP
can also do, even moreso if you have enough memory and
specify a large system cache (Google for that).

 

[Jim Howes]

I really don't like the prospect of RAID...I would need at least 2
identical drives with a reduction
in reliability

The whole point of RAID is to improve reliability by duplicating data
across redundant (R) arrays (A) of inexpensive (I) discs (D).

SOOO ! what about SCSI Hard drives ...I see Rpm's of 15000 ..access times
less than 1/2
that of standard SATA2

Access time to what?

Access time to a specific sector on a disk consists of the time it takes
the controller to tell the drive(s) what it wants, plus the time it
takes for the drives nearest that data to lift the data off the
platters, apply any necessary error correction, and squirt it down the
bus (be it SATA, ATA, or SCSI) to the host. For any given single-sector
transfer, the amount of time taken is so insignificant as to not be
worth considering. The difference for a single sector is hardly
different between an old MFM drive and a U320 SCSI drive. When it comes
to sustained transfer rates for consecutive sectors, that is another
matter, but for a home windows-based PC, is that really an issue?

Orthough there is now something called 'SERIAL ATTACHED SCSI'

If you are looking at something like the HP SAS controllers, which
implement RAID in hardware, they are very nice, but expensive;
Similarly things like the Compaq Smart Array devices; Given decent
driver support (which as ever, is dubious in win32), any form of
hardware of software RAID is equally comparable when properly set up.

I don't seem to see this approached ever mentioned in connection to IBM PC
comp. Home computers

Because _**HOME**_ computers generally don't require large arrays of
discs providing tuned I/O throughput as well as redundancy.

 

[Timothy Drouillard]

It depends how one prioritizes. Personally I hate drive failures,
and have been running the same set of four Seagate 15K.3
drives for almost five years now. They're built like tanks, run
at 30C at load and are virtually silent. My Adaptec 39320
controller cost $60 from eBay.

No argument there. SCSI Drives that are properly cooled will run for years
24/7/365. That's what they are designed to do in your average server.

No question that if your budget can afford it, SCSI drives are very quick.

A year or so at work where we do automotive component/vehicle testing, we
take digital photos to document parts as they are being tested.

For years, our photographer has been running Windows NT4 and Photoshop on a
system with Dual 650Mhz P3's with 1gig ram running on 10K Atlas HD's from
9gig to 74gig each.
We built him a new system from scratch, running a 3Ghz P4, 2gig ram, booting
from a 36gig Raptor and running Windows 2K.

He tried the new system for a couple of days and promptly went right back to
the previous system with the SCSI drives.

That's a great price for a excellent (if not the latest) SCSI card. It's
noit a RAID controller, but it's a rock-solid dual channel SCSI adapter.

 

[ejfowler]

You don't typically hear about home users using SCSI drives because of their
cost. Yes they are fast especially with the 15k rpm ultra 320 drives, but if
you consider the cost per capacity, you'll soon realize why they are
typically reserved for use in higher end workstations or servers.

If you're serious, consider the cost of a SCSI Raid adapter for your PC in
addition to the cost of the SCSI drives, which at the 15k rpm level come in
capacities far smaller that what's available in SATA drives these days for
the same cost.

For a home PC that you're describing as 'general purpose use', going to 15k
rpm SCSI is overkill unless you have plenty of money to throw at it for the
performance gain you would get.

If you think Raptors are expensive for the performance improvement you get,
wait till you get prices on 15K SCSI drives of the same capacity especially
considering that you need to add the cost of a good SCSI card.

If you want spped and safety, you can always consider a RAID 5 array or a
RAID 10 array.

With today's modern SCSI drives, you'll find the next bottleneck is
the your 33 MHZ 32 bit PCI bus. If you're serious about going SCSI,
you'll need to upgrade your mobo to PCI-X. There are workstation and
server boards out there with embedded SCSI controllers, or you can add
a RAID controller to one with a PCI-X bus.

 

[Bob Fry]

Reconsider RAID 0, with a small and fast HDD for a boot drive. I'm
running 4 disks in RAID 0, and someday I'll move things around to use
one disk for a boot disk and the others for RAID 0. Reliability?
Sure, it's less, but I've lost way more systems due to Windows
disasters than to HDD hardware failure. That's why now I have a
cheap, large capacity external HDD to which I do nightly backups.

 

[Bob Fry]

JH> The whole point of RAID is to improve reliability by
JH> duplicating data across redundant (R) arrays (A) of
JH> inexpensive (I) discs (D).

That was the original intent, but RAID has transmogrified into a
number of variations, some faster and less reliable, others more
reliable with less storage, etc.

 

[funfly3]

JH> The whole point of RAID is to improve reliability by
JH> duplicating data across redundant (R) arrays (A) of
JH> inexpensive (I) discs (D).

That was the original intent, but RAID has transmogrified into a
number of variations, some faster and less reliable, others more
reliable with less storage, etc.

I always thought the original definition was "redundant array of
independent disks" not inexpensive that came later

 

[kony]

A year or so at work where we do automotive component/vehicle testing, we
take digital photos to document parts as they are being tested.

For years, our photographer has been running Windows NT4 and Photoshop on a
system with Dual 650Mhz P3's with 1gig ram running on 10K Atlas HD's from
9gig to 74gig each.
We built him a new system from scratch, running a 3Ghz P4, 2gig ram, booting
from a 36gig Raptor and running Windows 2K.

He tried the new system for a couple of days and promptly went right back to
the previous system with the SCSI drives.

Your account is suspicous at best. There is no reasonable
explaination for it, the latter system is far faster and if
it were only a matter of drives then adding a 2nd Raptor
would have easily beaten the older system.

It says more than those who built the newer system didn't
take a look at the exact jobs being ran than anything else,
SCSI has no reasonable gain on today's workstations with old
10K drives, especially not with the controller sitting on a
PCI bus.

 

[Daniel James]

With my newly put together Home Computer ...games , general purpose use, C2D
E6600 @ 3.2 Gig, Geforce 8800 ...Win XP or VISTA.
I'm becoming increasingly aware of speed limitations with standard SATA2
hard drives ...

Disk is slower than RAM ... but the bottleneck in SATA is not the interface
it's the speed of the moving parts.

I have. looked at the Raptor Drives ...far to expensive for the little
improvement Re. standard SATA2 .

Raptors are essentially the same disks WD sell as SCSI disks but with a SATA
interface instead of SCSI. They are therefore priced similarly to SCSI drives,
and if Raptors are too expensive then I'm sure SCSI disks will be too.

Be aware that the improvement in speed with these drives is not huge ... the
higher spin speed does help with sustained data transfer (as I said, the
bottleneck is the disk not the interface -- even for PATA) and the shorter
track-to-track seek times help with random access. The improvement is
worthwhile where speed is of the essence, but you have to pay for it.

I really don't like the prospect of RAID...I would need at least 2
identical drives with a reduction in reliability (2 rather than 1 thing to
go wrong) ...

You can do RAID in different ways. Most of those ways don't require that the
drives are identical (though some hardware controllers may do). With most
flavours of RAID the logical disks need to be the same size, but the physical
disks can be different sizes (and part of the larger will be unused).

You can combine RAID0 (data striping, for speed) with (e.g.) RAID 1 (data
mirroring, for reliability) to get a speed increase without increasing the risk
of losing data if a drive fails -- you do need 4 drives for that, though, so
there is a cost, both in cash outlay and in sound and heat produced and
electricity consumed.

How much speed increase you actually get depends on the hardware and software
you use, and on the typical usage of the system. With striping you can
theoretically get the data off the platters twice as fast because you have two
disks providing the data ... but you also have two disks to wait for when
stepping between tracks, and the system takes some time to combine the two data
stripes once you have the data off the disk.

SOOO ! what about SCSI Hard drives ...I see Rpm's of 15000 ..access times
less than 1/2 that of standard SATA2 ...

At a cost at least equal to that of Raptors.

I have SCSI drives in this PC. I have a 36GB GB 10krpm U320 SCSI drive (that I
bought when the second 18GB U160 IBM/HGST Ultrastar drive decided to
demonstrate that Ultrastars and Deathstars weren't really all that different)
and it cost me about £100 about 18 months ago ... at which time I could have
bought 160GB of PATA drive for about half the money. This PC has a UW SCSI
controller on the motherboard, but no SATA and only ATA-33 PATA so that was a
no-brainer. When I bought the system (this one isn't homebuilt) SCSI drives
were as cheap as I've seen them relative to PATA, and the speed difference was
very significant. I do a lot of disk-intensive work, so it was worth the extra
cost.

Since then, SCSI drives have not come down in price as fast as IDE ones, and
SCSI controllers have become less common and more expensive. I wouldn't
recommend a SCSI-based system nowadays except possibly for some very
high-throughput server applications where a large volume of storage was not
required or cost was not an issue.

Orthough there is now something called 'SERIAL ATTACHED SCSI'

There are all kinds of fancy new technologies ... but they all cost money.

Have a browse around at www.span.com and compare the prices for yourself.

What might be of interest to you is the new solid-state drives that are
becoming available. They're based on Flash memory rather than a moving disk, so
their read speeds are orders of magnitude faster than disk and their write
speeds are several times faster than disk. The biggest I've seen mentioned are
only 32MB and cost several hundred pounds (though that may fall dramatically
when they become more widely available) but they're the only thing around that
offers hard-drive capacities with any real improvement in speed over SATA.

Here's a link, just one of many:
http://www.reghardware.co.uk/2007/01/04/sandisk_launches_flash_hard_drive/

Cheers,
Daniel.

 

[hdrdtd]

Nothing suspicous about it. Evidently in the photographers eye, the SCSI
based system appeared 'snappier' in performance.

Possibly the faster access time of the SCSI drives outweighed the higher
clock speed ans larger amount of ram in the newer system when it came to how
he actually used the system.

I do know that our digital photos are on the average around 5-15meg each,
and he usually has 20-30 open at any one time.

also keep in mind that the SCSI system runs on Windows NT which has less
overhead/bloat than Win 2K.

I was quite surprised myself when he decided to return to the NT SCSI system
with dual CPU's rather than use the much newer single 3Ghz P4 with more ram.

Oh well, to each their own.

It would be interesting to put a SCSI drive in the newer system and then
have him try it again.

 

[Andrew Smallshaw]

I always thought the original definition was "redundant array of
independent disks" not inexpensive that came later

It's the other way round. The original paper describing RAID is
up online at http://www.cs.cmu.edu/~garth/RAIDpaper/Patterson88.pdf
That uses the inexpensive expansion. Independent came later when
some marketroid didn't like the sound of the word "inexpensive".
In a way it makes much less sense - the whole point is that the
disks are not independent.

 

[Andrew Smallshaw]

I really don't like the prospect of RAID...I would need at least 2
identical drives with a reduction
in reliability (2 rather than 1 thing to go wrong) ...to get RAID speed
improvement with a
good level of error protection I would need SERIAL ATTACHED SCSI3 or more
drives ...all to complicated .

One recent development in computing that I'm not too keen on is
the introduction of castrated RAID 0, 1 and 1+0 capability on
motherboard. It creates the impression that that's all RAID has
to offer.

I'm most familiar with RAID on Unix servers, where RAID has usually
meant RAID 5 for at least the last 10 years. Your motherboard
won't support it, but you get the holy trinity of performance,
reliability and reduced wasted disk space. RAIDs 0 and 1 have
their uses, both they should be regarded as niche market stuff
rather than the be all and end all simply because your MB supports
them.

I don't seem to see this approached ever mentioned in connection to IBM PC
comp. Home computers
so I guess the answer is NO !!
Some one want to tell why ?

Most of my home machines use SCSI disks. This isn't primarily a
performance issue just one of cross platform compatibility. However,
you do also get a few other benefits: For a start, SCSI isn't
mass-market price-sensitive commodity hardware. That tends to
means the drives are far higher qulaity and much more reliable,
although that does come at a price.

Secondly, the SCSI interface is far smarter than ATA, and I suspect
that this is responsible for most of SCSI's real-world performance
even if the benchmarks don't show it. Transfers can be cancelled,
interleaved with other requests, or serviced out of order in a way
that simply isn't possible with ATA - if you've ever seen an ATA
machine's performance drop off to almost zero as two or more apps
'fight' for use of the disk, SCSI can handle this situation with
much more grace. In addition, a typical smart SCSI adapter is a
reasonably powerful computer in it's own right. They're capable
of offloading a lot of disk-related work from the processor.
Automatic scatter-gather can't be done with ATA - it's par for the
course with a good SCSI configuration. How relevant all that is
to the average home user I don't know, but I suspect it isn't very
much.

Downsides? Put simply, cost. The economics have changed over the
last few years. ATA has got better in performance terms, while
SCSI has if anything got still more expensive. Most of my home
machines do use SCSI but they're at least a couple of years old:
a new machine I'd have to consider ATA very carefully.

 

[Bennett Price]

With my newly put together Home Computer ...games , general purpose use, C2D
E6600 @ 3.2 Gig, Geforce 8800 ...Win XP or VISTA.
I'm becoming increasingly aware of speed limitations with standard SATA2
hard drives I have.
looked at the Raptor Drives ...far to expensive for the little improvement
Re.
standard SATA2 .
I really don't like the prospect of RAID...I would need at least 2
identical drives with a reduction
in reliability (2 rather than 1 thing to go wrong) ...to get RAID speed
improvement with a
good level of error protection I would need SERIAL ATTACHED SCSI3 or more
drives ...all to complicated .

SOOO ! what about SCSI Hard drives ...I see Rpm's of 15000 ..access times
less than 1/2
that of standard SATA2 ..the only way it could into go in my system is
(presumably)
with a controller card into the standard PCI slots (33 MHz) ...does that
have the speed ??.
Orthough there is now something called 'SERIAL ATTACHED SCSI'

I don't seem to see this approached ever mentioned in connection to IBM PC
comp. Home computers
so I guess the answer is NO !!
Some one want to tell why ?
(\__/)
(='.'=)
(")_(") mouse

Correct me if I'm wrong but I've always thought the speed advantage of
SCSI came into play when more than several un-RAID'ed disks were
attached to a controller and multiple users were all trying to access
data at the same time. Conversely, 1 SCSI disk vs. a similarly rated
IDE, SATA, disk etc. had little speed advantage when only 1 person was
reading or writing. Slower SCSI disks with an appropriate controller
could outperform very fast SATA disks in a typical server environment,
though that might not be true in a desktop 1 user PC.

 

[Andrew Smallshaw]

Correct me if I'm wrong but I've always thought the speed advantage of
SCSI came into play when more than several un-RAID'ed disks were
attached to a controller and multiple users were all trying to access
data at the same time. Conversely, 1 SCSI disk vs. a similarly rated
IDE, SATA, disk etc. had little speed advantage when only 1 person was
reading or writing. Slower SCSI disks with an appropriate controller
could outperform very fast SATA disks in a typical server environment,
though that might not be true in a desktop 1 user PC.

That's probably the single biggest adantage performance-wise. It
can come into play on a single-disk desktop in a multitasking
environment, although how much real use the average home user makes
of multitasking is debatable, particularly when it comes to intensive
tasks. When it does the difference is _huge_, but for most users
it will happen rarely if at all. I'm generally pro-SCSI but it's
getting increasingly difficult to justify the expense for desktop
systems, as I mentioned in another post.

 

[kony]

Nothing suspicous about it. Evidently in the photographers eye, the SCSI
based system appeared 'snappier' in performance.

Possibly the faster access time of the SCSI drives outweighed the higher
clock speed ans larger amount of ram in the newer system when it came to how
he actually used the system.

You assume old 10K SCSI has faster access time than a
near-current gen. 10K SATA drive?

I do know that our digital photos are on the average around 5-15meg each,
and he usually has 20-30 open at any one time.

If it is actually stressful on the disc subsystem, all the
more reason to use modern 10K drives, whether they be the
Raptor or new SCSI, rather than old. However, this load
would make it important to have more system memory too,
which the newer system had.

also keep in mind that the SCSI system runs on Windows NT which has less
overhead/bloat than Win 2K.

Win2k has very little bloat if set up for performance. That
goes back to matching the system config with the user's
needs.

I was quite surprised myself when he decided to return to the NT SCSI system
with dual CPU's rather than use the much newer single 3Ghz P4 with more ram.

Oh well, to each their own.

It would be interesting to put a SCSI drive in the newer system and then
have him try it again.

Or to do as I'd mentioned put a 2nd Raptor in and look at
when he finds issue with his jobs and address what is the
real bottleneck at that point.

 

[kony]

One recent development in computing that I'm not too keen on is
the introduction of castrated RAID 0, 1 and 1+0 capability on
motherboard. It creates the impression that that's all RAID has
to offer.

That might only be a subjective opinion. I think they
aren't trying to create impressions at all, just to offer
what is cheaper, considering RAID is a practically free
feature on motherboards and PCI cards costing under $20.

I'm most familiar with RAID on Unix servers, where RAID has usually
meant RAID 5 for at least the last 10 years. Your motherboard
won't support it, but you get the holy trinity of performance,
reliability and reduced wasted disk space. RAIDs 0 and 1 have
their uses, both they should be regarded as niche market stuff
rather than the be all and end all simply because your MB supports
them.

Cost is higher though, what would it do to PC sales if it
were an included feature? People can buy a RAID 5 capable
card for PC though, so it seems to be the consumer choice
for better or worse. It's also more likely an individual
user has less data than a company using a RAID5 capable
server, so it becomes more viable to use other methods of
backup and less critical, less loss (important business
functions stop) if that backup doesn't provide continual
uptime.