P5AD2, RAID 5, and more than 4 SATA drives ?

  • Thread starter Thread starter Snake Djip
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Snake Djip

Hi,

I'm trying to figure out what is the cheapest way to build a PC with
RAID 5 that can support up to 8 hard disks. I want to start with 4 or
5 hard disks, and I want to be able to add same-size drives as time
goes by. Note that the only reason that I want RAID 5 is for the
protection it provides. The performance gain (or loss) is not
important to me.

Now, according to http://www.tomshardware.com/storage/20041119/raid5-01.html,
it IS possible to have software RAID 5 on Windows XP.

So, what I'm really trying to figure out is this : what's the lowest
price I can pay in order to have a system that supports up to 8 hard
disks in a RAID 5 configuration.

I know I have the option of buying an 8-channel RAID 5 controller
(adaptec for example). What I want to know is : is there a cheaper
solution.

The P5AD2 motherboards support, it seems, up to 8 SATA hard disks.
What's not clear is : can 8 SATA hard drives be set up as an 8-drive
RAID 5 array with that motherboard, using Windows XP's software RAID 5
implementation ? Also, how easy would it be to increase storage space
by, for example, adding a fifth drive to a 4-drive array ? And so on
up to 8 drives ?

Thanks.
 
Hi,

I'm trying to figure out what is the cheapest way to build a PC with
RAID 5 that can support up to 8 hard disks. I want to start with 4 or
5 hard disks, and I want to be able to add same-size drives as time
goes by. Note that the only reason that I want RAID 5 is for the
protection it provides. The performance gain (or loss) is not
important to me.

Now, according to http://www.tomshardware.com/storage/20041119/raid5-01.html,
it IS possible to have software RAID 5 on Windows XP.

So, what I'm really trying to figure out is this : what's the lowest
price I can pay in order to have a system that supports up to 8 hard
disks in a RAID 5 configuration.

I know I have the option of buying an 8-channel RAID 5 controller
(adaptec for example). What I want to know is : is there a cheaper
solution.

The P5AD2 motherboards support, it seems, up to 8 SATA hard disks.
What's not clear is : can 8 SATA hard drives be set up as an 8-drive
RAID 5 array with that motherboard, using Windows XP's software RAID 5
implementation ? Also, how easy would it be to increase storage space
by, for example, adding a fifth drive to a 4-drive array ? And so on
up to 8 drives ?

Thanks.
Click to expand...

Enter "Software raid5" here, then click "SR Discussion Forums".
http://www.storagereview.com/search.html

Here is a sample discussion about monster arrays
http://forums.storagereview.net/index.php?act=ST&f=2&t=18670

Here is a cheap SIL3114 controller. $30 for four SATA ports.
http://www.newegg.com/app/ViewProductDesc.asp?description=15-124-020&depa=0
http://www.syba.com/us/en/product/43/02/05/index.html
http://www.siimage.com/products/product.aspx?id=28 (SIL3114 page)

Have fun,
Paul
 
I have the P5AD2 Premium mobo and love it. It actually has three separate
onboard RAID controllers. The INTEL ICH6R controller which allows for up to
4 SATA hard drives as RAID 0, or RAID 1. The second RAID controller is a
Silicon Image 3114R controller whcih will provide RAID 0, 1, 1 0, RAID 5,
and JBOD (Just a bunch of disks), again, using up to 4 SATA hard drives. The
third controller is an Intel ITE8212 IDE RAIDcontroller which provides
normal IDE or RAID 0,1,0+1, and JBOD using 2 Ultra DMA 133/100/66 IDE hard
disks. Bang for the Buck tells me that this mobo goes a long way to meeting
that need.

As a bonus this awesome mobo also comes with two Firewire IEEE1394b
connectors and PCI Express , two gigbit LAN controllers as well as a WIFI
802.11g, 8 USB 2 ports.

If you need more info, log onto the Asus website and download the manual.
Hope this helps a bit.
 
Well, the least cost would be to use the connectivity exisitng as per
Dogger's comments - to have system disc (hard mirrored) + n raid discs using
windows soft raid 5.

Windows software raid is very mature - it has been around since NT4 or
earlier...

I have run soft raid (1) on my server for a number of years (its a P2B-DS &
all SCSI) and never had trouble with it. This includes a system rebuild a
couple of years ago after the system disc dropped dead, several OS upgrades
and several service packs along with a few power failures. (the raid config
is auto detected on windows install).

I dare say that the references Paul provided will show up some issues.

If your system is not demonstrably highly stable, expect the same of your
RAID.
If the discs you use are not quaility """"

etc.

Many will say soft raid performance sucks. Well, if you have a quality hard
raid controller at hand and compare the two, yes it does but then they cost.
However if you compare it to non raid - its a few % slower at most. This
option is chosen for resilience + ECONOMY + sod the v.slight performance
loss.

The issue you may have is having a bunch of discs on the SATA controllers in
a non h/w RAID config (IE JBOD).

If I where setting this up I would:
- very thoroughly test system stability: memtest86 for 12 or more hours,
prime95, verify CPU temps are as good as you can get, verify PSU voltages
are stable under load with a fully configured system.
- test each drive, surface scan, bulk file copies etc. MS used to have a
SQLHDTest utility, but it does not work under XP / Server 2003 - it would be
ideal... (it work under NT).

All this testing is pre-emptive. I do it as standard on servers that are to
run 24 x 7.

I suggest you try it out with 3 discs - fail a disc by pulling out the PSU
cable when off and learn how it behaves, how to rebuild the array etc. Don't
forget that the SATA discs are not truly hot swap yet (perhaps they are with
ICH6R). Also test performance as discs are added to the array - some RAID 5
implementations are truly dumb and nead to re-read all sectors at the same
position to rewrite the XOR data so they get slower with more drives.

HTH

- Tim
 
Thanks for the replies.

I've downloaded the mobo manual. It seems that all drive connector
groups on the motherboard can be set as non-RAID, and I am guessing
that this means that I could use all hard disks with XP software RAID.

From what I understand, there are 8 SATA connectors on the board (for
up to 8 SATA drives), and there are also 3 IDE connectors, 2 of which
can be used for on-board hardware RAID, or not... This would mean a
maximum of 6 IDE drives.

Since I'm going to be using a DVD-Writer in this machine, and since
I've read somewhere that it's not a good idea to connect an optical
drive on the same connector as a HD, my conclusion is that this
motherboard would theoretically let me connect 8 SATA HDs and 4 IDE
HDs, for a total of 12.

The first question that comes to my mind now is : can I mix
same-capacity SATA and IDE drives in a XP software RAID setup ? What
are the implications if it is possible ?

The second question is : since I'm using XP to control the RAID array,
this means XP has to be on a separate drive (does it?). Should I buy
a 10k drive for the OS, and regular 7.2k drives for the data ?

My last question is : what's involved when I decide that I want to add
another drive to increase capacity ? Let's say I have 4 drives in my
RAID array, and I decide to add a fifth one ? Is this at all possible
without reformatting (and losing the data on the existing drives) ?

3 questions, and really hoping for 3 answers :-)

Thanks again
 
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