"How I built a 2.8TB RAID storage array"... 7 months later


P

Parag Baxi

Shamelessly taken from this thread:
http://groups.google.com/group/alt....54f5d?q=storage+array&rnum=2#f8479484a5254f5d

WARNING: I'M A NEWBIE AT BUILDING SYSTEMS. I'm asking for advice.

I have now read the above thread about 6 times over the past 4 days.
This thread has become a starting point for so many learning points to
undersand exactly what was being written. I have learned a great deal
and am inspired to build one myself.

My question on this thread is, now that it's been 7 months since its
inception, would YOU do anything different. I'll copy and paste his
specs and add what I want to do. Please keep in mind I'm a newbie at
building systems but I'm very persistent and willing to listen and
question. Now, on we move!

STORAGE MEDIUM
Actual: Nine 400GB PATA drives;
mine: i want basically same thing, but my controller + case allows for
more extensibility. hoping to buy as they come on sale (individually
or same time)

CASE
Actual: Antec 4U rackmount case.
mine: Lian LI V PC-V2100A Plus
(http://www.newegg.com/Product/Product.asp?Item=N82E16811112093#DetailSpecs)

MOTHERBOARD
Actual: Gigabyte X5DAL-G Intel server motherboard
mine: i'm really lost here... he lucked out on a cheap deal with ebay.
if i were to buy one from them, it'd be very difficult to search by
motherboard. what other MBs do you recommend?

CONTROLLER CARDS
Actual: Two 3Ware 7506-4LP cards.
mine: i was thinking, why not use my case to the max and get a 7506-8LP
now, and when it fills up, get another one. the case holds 7 External
5.25" Drive Bays and 12 Internal 3.5" Drive Bays

RAM
Actual: 2 GB DDR
mine: i'm thinking 1 GB is enough. DDR or DDR2?
SOFTWARE
Actual: Linux software RAID 5 and JFS.
mine: i'm lost on any other way. i read his link and feel i'm not
ready to experiment
COST
him: 4100 $
willing to shell out 3000 $ and add HDs as they come cheap.

ASSEMBLY: SOFTWARE
Actual: Fedora Core 3 & JFS
mine: i don't know if Debian can support this hardware, but that's what
i prefer.'

ok, again, i don't know much so there is probably 10 things wrong with
each choice i made. I'd appreciate if you tell me why it's wrong. I
appreciate it that you even read this far.

-- ghee22
 
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P

Parag Baxi

SATA would def. be easier to fit in the case. The problem is SATA HDs
are generally 2 times more expensive per unit GB
(http://froogle.google.com/froogle_c...459099906820246&btnG=Search+Froogle&scoring=p
). Many Ultra ATA HDs come on sale. I have bought 3 HD 300 GB+ for ~
100 $ each. When taking into account 8 to 12 HDs, it is more cost
effective to get ATA.

Do you know where I can obtain SATA HDs for about 200 $? This will
probably make me think twice.

ACTUALLY: I just looked this up again and it looks like they are about
the same price.... What else do i have to consider when gettting SATA
HDs?

While it is true that SATA has a higher speed capacity than ATA and
allows for better compatibility with hardware RAID, "the transfer rate
is only slightly faster" than Ultra ATA 133 and software raid is going
to be used for the reason posted in reference thread.

George Pontis wrote:
If you want to go much cheaper, you could get a non-server motherboard
with multiple Serial ATA capability. For instance, the Asus A8N-SLI
Premium has 8 S-ATA II connectors which can be arranged into two banks
of RAID 0, 1, or 0+1 (I think). With a modest CPU it would only cost
$350. SATA would be easier to neatly cable up inside your case too. You
can use ECC RAM in this motherboard.

Or, you use Areca ARC1220 in the same mobo for 8 SATA-II in any RAID
0,1,5, or 6.

I don't see why you need a server motherboard, except that the 3Ware
board has a PCI-X interface for better bus speed. The Areca uses PCI-E
X8 which is more modern and much faster yet. You could plug it into an
X16 slot on the motherboard.

So there are some thoughts. I don't have any real experience with this
so do check for yourself if this hardware would all be compatible.
 
J

Jim

I only have one problem w/ the design -- he commits to the storage before
it's actually used.

Problem w/ this is, most of the storage will not be used for a VERY long
time (unless he's dumping DVDs or somethin' on a regular basis). A better
design would provide the POTENTIAL for 2.8TB storage, but only COMMIT to it
"on demand". IOW, add HDs only when the demand is present. Perhaps when
some threshold is passed (e.g., < 20% free space). This way, he can either
add the same storage (e.g., 300GB drives) when they're much cheaper in the
future, or larger HDs (500GB ?) at the prices he's paying today. Just look
what he paid for those drives back in Feb., $230! Heck, today these go for
$80-90 (after rebate). And I bet he's not even consumed 30% of the original
capacity, maybe far less.

Btw, I'm not sure why he says that Promise RAID PCI cards do not do "true
hardware RAID". Can't speak to the Highpoint or Adaptec cards, but the
Promise card does hardware RAID, for sure. Heck, I use a Promise FastTrak
100 TX2 myself. You configure it on boot-up, using its own BIOS. Windows,
Linux, DOS, etc., are completely unaware of its presence, thus no
dependencies. Software based RAID would require Windows (for example)
support. In fact, years ago I used Windows NT RAID myself. So I don't
understand the author's criticism of the Promise hardware. It's every bit a
hardware RAID solution as 3Ware (which may be better for other reasons, but
not because of software vs. hardware RAID).

Anyway, I just not a big believer in designs that commit to large storage
up-front. Most times, you're simply wasting money, lots of it.

Jim
 
P

Parag Baxi

I believe you're correct.. the pCI hard you mention (Promise RAID) is
at least 305 $ on froogle. is RAID necessary on this when it's hosting
just media files? That depends on user; i don't think it is..

you seem to know your hardware, do you have any clue if what the rest
of the hardware is compatible with each other?

and do you think SATA is more important to have than ATA?
 
J

Jim

Parag Baxi said:
I believe you're correct.. the pCI hard you mention (Promise RAID) is
at least 305 $ on froogle. is RAID necessary on this when it's hosting
just media files? That depends on user; i don't think it is..

Depends on YOUR definition of necessary. If it was *my* data, I'd consider
most of it NOT expendable. Contrast this to my OS installations, which I do
consider expendable. It's only an inconvenience if I lose my OS, but worst
case, I can always rebuild. But if I lose my data (word docs, tax returns,
family photos, audio/video collection, etc.), which may have taken years to
collect, most of it is irreplaceable. That's why I would typically opt for
RAID 1 (mirroring). Yes, it doubles the cost and increases complexity a
bit, but again, it all depends on how much value you place on the data, and
what losing it would mean to you.
you seem to know your hardware, do you have any clue if what the rest
of the hardware is compatible with each other?

I only skimmed the article, noting the high points. I assume if he got it
working it was compatible.
and do you think SATA is more important to have than ATA?

In the case of data storage, no. Truth be told, SATA offers very little if
anything over ATA, at least today. Most SATA drives are only PATA drives
which have been modified to use the new SATA interface. IOW, they're PATA
drives through and through, same mechanics. The only exceptions we've seen
to date are the WD Raptors, which have been redesigned, and turn @
10,000RPM. Using the Raptors would increase performance, for sure. But in
the case of data, I'm not sure that SATA is worth it. I tend to separate
the needs of the OS from my data, both logically and physically. I consider
SATA, at least today, to be best suited for optimal OS performance. But
when it comes to data, SATA is usually overkill, and simply wasteful, esp.
if you're not using the Raptors. You're simply paying a premium price for
nothing more than an interface change. Most HD drives today, SATA or PATA
(excluding the Raptor) can't do much better than 30-35MB/sec anyway, so they
can't even saturate an old ATA66 interface, let alone ATA100 or ATA133
(making these latter updates pretty much a scam). But even with the Raptors
you won't be seeing anywhere near the SATA's 150MB/sec peak performance,
because as with PATA, even a Raptor can't saturate its new SATA interface,
not even close.

Jim
 
D

DevilsPGD

In message said:
Depends on YOUR definition of necessary. If it was *my* data, I'd consider
most of it NOT expendable. Contrast this to my OS installations, which I do
consider expendable. It's only an inconvenience if I lose my OS, but worst
case, I can always rebuild. But if I lose my data (word docs, tax returns,
family photos, audio/video collection, etc.), which may have taken years to
collect, most of it is irreplaceable. That's why I would typically opt for
RAID 1 (mirroring). Yes, it doubles the cost and increases complexity a
bit, but again, it all depends on how much value you place on the data, and
what losing it would mean to you.

Agreed, plus a backup is essential too, since RAID doesn't protect
against user error (deletion/format/etc) or devastating hardware events
(a cheapo power supply that decides to surge as it dies could take both
drives out, a fire that physically destroys the system, or loss of the
entire PC)
 
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