Need advice on configuring raid array - or should I


C

conf22

I am planning a new workstation.
I will be using it for several intensive tasks (both processor
intensive and I/O intensive), including voice recognition, video
editing and image editing (large files).

I am considering building a RAID array (RAID 5 sounds the best balance
of speed / safety).

I was considering:

8 Western Digital SATA II 320gb drives
An external enclosure (to keep them seperate from the PCs heat)
A 3ware 9550sx RAID controller.

My questions are:

Is this going to be faster for my purposes than just using individual
drives W/O RAID?

Should I use the drives as one array IE 8 drives = n=8 n-1 = 7 x 320
= 2.24 T array
or
Should I use them as two smaller arrays IE 4 drives = n=8 n-1 = 3x320 =
960 gb per array

Clearly the first option (one big array of 8 drives) gives me more
usable space. My question is, is it faster or slower than two smaller
arrays?

Thanks
Jeff
 
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R

Rod Speed

(e-mail address removed) wrote
I am planning a new workstation.
I will be using it for several intensive tasks (both processor
intensive and I/O intensive), including voice recognition, video
editing and image editing (large files).
I am considering building a RAID array (RAID 5
sounds the best balance of speed / safety).
I was considering:
8 Western Digital SATA II 320gb drives
An external enclosure (to keep them seperate
from the PCs heat) A 3ware 9550sx RAID controller.
My questions are:
Is this going to be faster for my purposes
than just using individual drives W/O RAID?

Nope, not with RAID 5 enough to matter.
Should I use the drives as one array IE 8 drives = n=8 n-1 = 7 x 320
= 2.24 T array
or
Should I use them as two smaller arrays IE 4 drives = n=8 n-1 = 3x320
= 960 gb per array
Clearly the first option (one big array of 8 drives)
gives me more usable space. My question is, is
it faster or slower than two smaller arrays?

Not enough speed difference to matter.

The only thing that makes any real sense speed wise is a very
fast drive for the stupid Photoshop swap drive if you use that.
 
C

CJT

I am planning a new workstation.
I will be using it for several intensive tasks (both processor
intensive and I/O intensive), including voice recognition, video
editing and image editing (large files).

I am considering building a RAID array (RAID 5 sounds the best balance
of speed / safety).

I've heard of people choosing RAID 5 because it provides safety and
economy, but I don't generally see "speed" in the same sentence.
I was considering:

8 Western Digital SATA II 320gb drives
An external enclosure (to keep them seperate from the PCs heat)
A 3ware 9550sx RAID controller.

My questions are:

Is this going to be faster for my purposes than just using individual
drives W/O RAID?

I seriously doubt it.
 
C

conf22

Unfortunately, that is what I was afraid of.
The thing I like the best about it was being able to use a pair of
multilane cables and have the whole mess external.

If I were to go with a smaller number of larger drives, is there a
decent way to house them and use them externally w/o RAID

I don't want to sacrifice speed. I want the fastest drives I can get
but really want them outside the main unit to keep the heat to a
minimum.

If I use normal SATA2 I could run cables to an external housing but
then I would need one for each drive. Even if I used (4) 500GB Western
Digital drives (my original idea) I'd have four seperate cables running
between the two enclosures. Is there an simple way to do this neater?
In other words, to have one cable w/o making it a RAID array?

Thanks,
-Jeff
 
B

Beemer Biker

I am planning a new workstation.
I will be using it for several intensive tasks (both processor
intensive and I/O intensive), including voice recognition, video
editing and image editing (large files).

you dont why RAID is needed. is this a mission critical application such as
(for example) a forensics lab where you got to rebuild a disk in background
while continuing your work? will one or two of the drives be hot swappable
spares?
I am considering building a RAID array (RAID 5 sounds the best balance
of speed / safety).

OK, just wondering though if you have worked with any raid systems before?
Just make sure the OS and pagefile are on the non-raid disk and you should
be ok speed wise. If you are also planning on running a database (sql
server or whatever) You might want to invest in a xeon or real dual
processor system.
I was considering:

8 Western Digital SATA II 320gb drives
An external enclosure (to keep them seperate from the PCs heat)
A 3ware 9550sx RAID controller.

I have worked with adaptec raid scsi controllers, I assume 3ware has good
support, firmware update support, etc. You better check Western Digital
also has a support forum, you might want to register over there and ask
about raid in the SATA forum. I remember doing a rebuild of a disk at the
cmos level (when the system rebooted it said a rebuild had to take place).
It took 24hours on a 3 drive raid5, each drive was only 36gb. Once the
adaptec disk manager was installed under xp pro, the same rebuild took only
minutes. You should be thinking about a good case and motherboard. The
drives should all be at the same firmware level. Make sure they can be
flashed. We put together about 40 raid5 systems and the seagate scsi's were
not all at the same firmware level. Getting on seagate site and looking up
the firmware showed there were known timeing issues and all the drives had
to be brought up to the same level I dont think you want to buy 3 drives
now to get started with raid5 then a few months later buy another 3 and find
they dont match.
My questions are:

Is this going to be faster for my purposes than just using individual
drives W/O RAID?

If it is set up wrong it will be a disaster. You would not think a customer
would order 64 bit scsi boards and only 32 bit slot motherboards, but S**T
happens when you roll your own.
Should I use the drives as one array IE 8 drives = n=8 n-1 = 7 x 320
= 2.24 T array
or
Should I use them as two smaller arrays IE 4 drives = n=8 n-1 = 3x320 =
960 gb per array

there is more to raid 5 than those options. How do you want to implement
reliability? Do you want redundency and to have spare hot swap ready to
plug in?
Clearly the first option (one big array of 8 drives) gives me more
usable space. My question is, is it faster or slower than two smaller
arrays?

IANE on raid, you might want to go to google and search thru the
microsoft.public.* newsgroups. While "raid" does not show up, you can get
hits on raid5 and 3ware like this:
http://tinyurl.com/f65jn


--
=======================================================================
Beemer Biker (e-mail address removed)
http://ResearchRiders.org Ask about my 99'R1100RT
http://TipsForTheComputingImpaired.com
=======================================================================
 
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C

conf22

Okay let me clarify.
This isn't anything mission critical. Redundancy is nice but not
imperitive.
Speed is the most important (but I'm not willing to gamble on just a
striped set).
I liked the idea of RAID for this because I thought RAID 5 might buy me
some speed. I also like the idea of using eSATA to move the drives out
of the workstation and into a seperate box.
From what I am hearing (and what I just read elsewhere), I can buy 4
bay eSATA enclosures with multilane and use that w/o RAID. I can use 4
500GB Western Digital drives and the whole thing will be faster and
cheaper but not redundant.

Are there any pitfalls to this that I am missing?
Are there any problems with using eSATA?

Thanks,
Jeff
 
C

CJT

Unfortunately, that is what I was afraid of.
The thing I like the best about it was being able to use a pair of
multilane cables and have the whole mess external.

If I were to go with a smaller number of larger drives, is there a
decent way to house them and use them externally w/o RAID

I don't want to sacrifice speed. I want the fastest drives I can get
but really want them outside the main unit to keep the heat to a
minimum.

If I use normal SATA2 I could run cables to an external housing but
then I would need one for each drive. Even if I used (4) 500GB Western
Digital drives (my original idea) I'd have four seperate cables running
between the two enclosures. Is there an simple way to do this neater?
In other words, to have one cable w/o making it a RAID array?

Thanks,
-Jeff

There are other forms of RAID than RAID 5. Some of them can be
faster than individual drives, particularly if you do a lot more
reading than writing.

Fibre or even copper SCSI might be a better solution if speed is
critical, but they cost $$$.

If it were me, I'd probably think again about the separate enclosure
constraint. It might be better to just find a well cooled server case
and put everything in it.
 
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O

Odie

Okay let me clarify.
This isn't anything mission critical. Redundancy is nice but not
imperitive.
Speed is the most important (but I'm not willing to gamble on just a
striped set).
I liked the idea of RAID for this because I thought RAID 5 might buy me
some speed. I also like the idea of using eSATA to move the drives out
of the workstation and into a seperate box.

bay eSATA enclosures with multilane and use that w/o RAID. I can use 4
500GB Western Digital drives and the whole thing will be faster and
cheaper but not redundant.

Are there any pitfalls to this that I am missing?
Are there any problems with using eSATA?

Thanks,
Jeff

One of the most important issues is going to be your choice of RAID
adaptor.

In your position, I would use something like an Areca ARC-1220
PCI-Express with 8 ports.

Get yourself 4 x Seagate 500GB drives and use them in a RAID 0 array.
You could put another, single drive on there for use as a swapfile.

Be aware this is NOT advisable for mission-critical stuff, and always
keep regular backups to at least two other, single drives, as well as
DVD if practical. The other drives should be on bog-standard IDE (PATA
or SATA) motherboard connections and not on boutique controllers.

You should also consider a dual-core CPU; Intel seem to have the edge
over AMD for video editing, although AMD win on all other counts,
including price.

Don't use Western Digital drives; firstly, I don't consider them
reliable (of course, there will be a number of users in this forum who
will swear by them) and there are certain anomalies when using some
models in RAID.

SCSI is great, too - but a 2TB RAID array in a decent SCSI setup will
cost a little more than an equivalent SATA setup.


Odie
 

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