RAID 1 solution for desktop

Hello All,

I need to implement a RAID 1 solution for a high end desktop machine,
and I'm considering 2 options:

1) Use the onboard(cheap) SATA RAID controller on my motherboard with 2
Western Digital Raptor WD740GD 74GB 10K SATA drives.
Approximate cost: $400.00

2) Purchase new SCSI RAID controller with 2 high speed SCSI drives such
as the Maxtor Atlas II 15K 73GB drives.
Approximate cost: $1500.00

My question is: Will the superior performance of the SCSI drives be
realized considering the PCI Bus architecture of my MB? Especially
considering the $1100.00 difference?

Also, I'm sure the reliability of the SCSI solution surpasses the SATA,
but both hard disks listed have a 5 year warranty.

Opinions?

TIA,
Dave

David Beasley wrote:
Hello All,

I need to implement a RAID 1 solution for a high end desktop machine,
and I'm considering 2 options:

1) Use the onboard(cheap) SATA RAID controller on my motherboard with 2
Western Digital Raptor WD740GD 74GB 10K SATA drives.
Approximate cost: $400.00

2) Purchase new SCSI RAID controller with 2 high speed SCSI drives such
as the Maxtor Atlas II 15K 73GB drives.
Approximate cost: $1500.00

My question is: Will the superior performance of the SCSI drives be
realized considering the PCI Bus architecture of my MB? Especially
considering the $1100.00 difference?

I'll let you decide if it's worth the money, but what kind of
performance do you need? High transfer rate? Quick response time? Can
you estimate a value for one or the other?

Hard to tell not knowing what you need, but eyeballing, going SCSI
seems overkill.

Also, I'm sure the reliability of the SCSI solution surpasses the SATA,
but both hard disks listed have a 5 year warranty.

That means that you'll get your money back or a replacement if
something breaks before. Is not a prediction of how long either model
will last, just to be clear.


Opinions?

TIA,
Dave

On 13 Oct 2005 14:00:10 -0700, "David Beasley"
wrote:

Hello All,

I need to implement a RAID 1 solution for a high end desktop machine,
and I'm considering 2 options:

1) Use the onboard(cheap) SATA RAID controller on my motherboard with 2
Western Digital Raptor WD740GD 74GB 10K SATA drives.
Approximate cost: $400.00

2) Purchase new SCSI RAID controller with 2 high speed SCSI drives such
as the Maxtor Atlas II 15K 73GB drives.
Approximate cost: $1500.00

My question is: Will the superior performance of the SCSI drives be
realized considering the PCI Bus architecture of my MB? Especially
considering the $1100.00 difference?

Also, I'm sure the reliability of the SCSI solution surpasses the SATA,
but both hard disks listed have a 5 year warranty.

Opinions?

TIA,
Dave

What are the requirements? If safety is the driving factor for this
mirror then it makes little difference in the long run, you've got 2
copies online. If performance is the driving factor then what is the
application? Streaming media or large sequential writes/reads will
probably not see a noticeable difference between them. But if you're
IO is more random in nature then scsi will give a significant boost.

~F

Thanks for the replies guys.

Security of data is the number one priority, followed very closely by
performance. Usage will be almost entirely reading/writing large files,
so transfer rate would drive the performance need. This is a graphic
design/image manipulation workstation utilizing Photoshop, Illustrator,
InDesign, Quark Xpress, and CorelDraw intensively.

If I'm reading y'all correctly, there will be minimal performance gains
in my situation from going SCSI, which is what I figured initially. I
only considered the SCSI solution because I bought this machine
explicitly for performance, and I hate to slow it down for mirroring.
Initially I had a RAID 0 setup for performance, with nightly backups.
But slowly I began slacking with the backups and got burned badly when
one of the drives went down.

One other related question: The onboard RAID on the MB(Asus P4C800
Deluxe) is the Promise PDC20378 controller chipset. From what I've read
in other forums, this is actually a software RAID controller, no? Would
adding a hardware RAID controller give noticeable performance benefits?
If so, any recommendations for a SATA RAID controller? Intel SRCS16,
LSI MegaRAID, and 3Ware Escalade all seem affordable.

These are specs on the system if it matters:
3.2 Ghz Pentium 4 processor
Asus P4C800 Deluxe MB
2 GB RAM

Thanks again for the help,
Dave

On 14 Oct 2005 11:02:02 -0700, "David Beasley"
wrote:

Thanks for the replies guys.

Security of data is the number one priority, followed very closely by
performance. Usage will be almost entirely reading/writing large files,
so transfer rate would drive the performance need. This is a graphic
design/image manipulation workstation utilizing Photoshop, Illustrator,
InDesign, Quark Xpress, and CorelDraw intensively.

If I'm reading y'all correctly, there will be minimal performance gains
in my situation from going SCSI,

Correct. SATA should suit you just fine.

only considered the SCSI solution because I bought this machine
explicitly for performance, and I hate to slow it down for mirroring.

It can actually speed up reads since it can request parts of the data
from 2 spindles.


One other related question: The onboard RAID on the MB(Asus P4C800
Deluxe) is the Promise PDC20378 controller chipset. From what I've read
in other forums, this is actually a software RAID controller, no? Would
adding a hardware RAID controller give noticeable performance benefits?
If so, any recommendations for a SATA RAID controller? Intel SRCS16,
LSI MegaRAID, and 3Ware Escalade all seem affordable.

Software RAID 1 is really not cpu intensive so I don't think you need
to worry about hardware raid. Now if you were doing raid 5 that would
be different.

I can speak to the LSI and 3Ware controllers, both are fine. If
you've got money you're looking to spend then go for it. But like I
said, I don't really think you need to.

~F

David Beasley wrote:
Thanks for the replies guys.

Security of data is the number one priority, followed very closely by
performance. Usage will be almost entirely reading/writing large files,
so transfer rate would drive the performance need.

In that case, you may actually be better off with the newest
high-density 7200 rpm SATA drives. And as long as you mirror them data
security (availability) should not suffer measurably from what you'd
have with higher-end drives.

In any event, you'll want to be using a file system that gives some
priority to keeping the files unfragmented (or defragment the disks
frequently while they're otherwise idle).

- bill

Bill Todd wrote:
In that case, you may actually be better off with the newest
high-density 7200 rpm SATA drives.

Oh, how so? Do you have any specific recommendations?

David Beasley wrote:
Bill Todd wrote:

In that case, you may actually be better off with the newest
high-density 7200 rpm SATA drives.


Oh, how so?

In transfer rate, of course: the context to which I was replying.

The highest-density new SATA drives rival or exceed anything else on the
market in this area, because while they spin more slowly their linear
density is high enough to compensate.

- bill

Many thanks for the help guys. I probably would have wasted money
without your advice. I've decided to go with
160GB Seagate Barracuda 7200.9 hard drives using the onboard RAID.
Total cost: $200.

Dave

In article . com,
David Beasley wrote:
Security of data is the number one priority,

What happens if one of the drives in the mirror pair is bad? You
might not even notice for weeks that you have lost one drive, and run
in degraded mode. At this point, you suddenly become vulnerable to
the second drive failing. Unless you have hot spare drives installed
and have set up the RAID controller to automatically rebuild onto the
hot spare, this is a real risk. Make sure there is some sort of
monitoring program set up.

Also, what happens to operator error (deleted the most important
file), and OS error (operating system scrambles the file system)?
Unless you have a snapshot solution and/or good backup, these are the
most likely cause of data loss, once you have mirrored the data. So
RAID doesn't save you from having to do backups.

If I'm reading y'all correctly, there will be minimal performance gains
in my situation from going SCSI

True for sequential bandwidth. Also, SCSI has a large cost penalty.

I would still use SCSI disks. Why? They are faster in seek times,
and that matters a little too. It can matter a lot of you have
multiple applications running, each of them doing sequential work.

And WAY more reliable. Yes, I know you have RAID-1. But I like belt
and suspenders. And you'll have less time spent on occasionally
(every few years) replacing disks.

Look at it this way: The cost of this workstation going down is
probably the salary (or lost productivity?) of the person using it.
At a cost of maybe $150K per year (with overhead and such) for the
user, that's $75 per hour. Compared to that, the extra cost of SCSI
is just a few hours less trouble.

If so, any recommendations for a SATA RAID controller? Intel SRCS16,
LSI MegaRAID, and 3Ware Escalade all seem affordable.

I've used both LSI and 3Ware, both with excellent results. LSI is a
little more expensive, but has slightly better performance; 3Ware is
more common and less expensive. This is not an endorsement, nor do I
have anything bad to say about the Intel card (never used one). As
you are not doing RAID-5 (in particular not RAID-5 in degraded mode),
performance of the RAID card is probably irrelevant; the disks will be
the bottleneck. Even the On-board Promise chip might be good enough -
but I would test that.

Enjoy your new fast (and reliable) system.

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