Sata 3.0 Raid 10 Configuration, Seperate Arrays on Same Drive Set or One Array and Partitions?

I have purchased a SATA 3.0 rocketRAID 640 and four Sata3.0 640Gb Western Digital Black Edition HD's.

My current setup is one 64Gb crucial SSD for Windows 7 x64, and plan to use the 4 drives in Raid10.

What is the best practice on Raid Arrays managed by a separate controller. (Forgetting the SSD)  If I wanted to install the OS on the 4 drives, would I get better performance if I created let's say an 80Gb Raid0 array across all four drives and used the remaining space for a Raid 10 array?  This would mean 2 raid arrays on the same controller across the same drives. OR.  Would it be best to just create 1 Raid 10 array and within that array create 1 small partition for the OS and one partition for Storage?  Throughout much searching I have yet to find a complete answer.  

Does the performance decrease when 2 arrays are created across the same drives? Is partitioning a better practice then separate arrays?  For Example, let's say I wanted to have some redundancy in my OS partition or array.  Would it be better to create a Small Raid 10 array for the OS and a large Raid10 array for storage, or a single Raid 10 array and 2 partitions?

Even if I don't install an OS, on one partition, would creating two Raid 10 500Gb array's across the same 4 drives perform worse/better than one Raid 10 array and 2 500Gb partitions?

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stick with plan A.
put the OS on your SSD and raid 10 the four SATA drives.
Reason is two fold, best practices for Windows says don't put the OS on a raid (the verdict is still out IMHO)

I wouldn't use the multiple array feature, recovery would be complicated.  You'll get redundancy and speed with the RIAD 10 array, but you will loos a little hard drive space.  Note: Rocket raid will make you install software in windows to manage the array.

install apps, games, video, ect. on the array.  you can break it up into partitions or one large volume if you want.  I would suggest purchasing another SATA drive, leave it unused in a drawer,  if one of the four drives go bad, just swap it out and wait, it will rebuild the data.
Plus you'll have a place to keep a good image of your OS.

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A high end raid card may allow mirrored drive to be used differently at read time.
For example on read io, inner tracks from drive 1, outer tracks from drive 2; that would lower the avg read access time (Of course, write io requires the same write io on both drives and can not provide any gain in such case)

That kind of feature would allow to dream on some performance enhancement using 2 arrays...

Now, back to the basics:
-Windows OS on the SSD using a 64KB aligned partition (You can partition your SSD from another pc otherwise your default partition at Win2003-XP installation time will be 31.5KB aligned)
-1 array in RAID 10 using 256KB (or 1MB if you are storing many large files like Photos or Movies) stripe size, 1MB alignment and 64KB NTFS cluster size (care : many disk utility - defragment, backup, etc - does NOT work with non-4KB cluster size)
-Disable useless features: LastAccess timestamp & 8.3 filename generation
   fsutil behavior set disablelastaccess 1
   fsutil behavior set disable8dot3 1
MARAGONLLCAuthor Commented:
Thank You heideld and Nog Schmu, but my question isn't really getting answered.

 I know the SSD is a good option for the OS, but my question is without the SSD.  Up until about 2 days ago I didn't have an SSD, and I was perplexed by this question.  SO, assuming I was putting the OS on the Raid Array, what would be the best way to do it with Raid 10.  2 arrays, or 2 partitions, etc... (Read my question  above)

BigSchmuh:  you were onto something when you said "(Of course, write io requires the same write io on both drives and can not provide any gain in such case)"   If performance isn't better, is it worse if 2 arrays are across the same 4 drives?  (Taking the SATA 3.0 into consideration, and the external raid controller)

It is very similar to what Intel does in their Matrix technology, however, I really haven't been able to find a good direction on how the performance is affected, and redundancy.

 I have come across some good reads  but no facts.
OS io usage are mainly random write oriented and I think it requires a 4KB NTFS cluster size
Although, you have to take care of allowing a disaster recovery plan that does not require 10 "raid" experts to be involved in

Apps and Data may be very different:
-Writing movies/photos to be streamed means a RAID 5/6/50/60 parity array would be great
-Databases requires random io as well
-64KB NTFS cluster size DOES enhance performance (even if you have to take care of your disk utility to explicitly support 64KB cluster size) - This is a mandatory point for parity arrays and a good practice on mirrored arrays

So your answer depends on applications and datas involved because they may have different io usage pattern.
If the io usage patterns are very different (1 random 1 sequential), you may physically separate the HDD : 2 RAID1 arrays
Otherwise, putting everything on a single (4KB cluster size) array may be easier and faster
and :
-having 2 arrays accross the same drives is useless in most case
-one case may happen : OS 64GB partition is copied on a 64GB partition on a drive thus leaving 3x 64GB available for a 128GB RAID 5 array (to use on unopen timeframe for backup2disk or very rarely used files) stored on 4x HDD that are mainly used for a 2x336GB RAID 10 array
-Sata 3.0 does nothing really better than Sata 2.0 in your case
MARAGONLLCAuthor Commented:
I agree, that a single RAID 1+0 will keep things simpler for recovery purposes, and I've decided to stick with the SSD OS, and a Single Raid10 array for programs/ data/ and some storage.  

MARAGONLLCAuthor Commented:
I've attached an illustration I created to better illustrate what it is I'm asking.
I'm a little confused, the illustration makes it looks like you really want to put the OS on the RocketRaid 640, but you stated you are going with the OS on the SSD and and a single Raid 10.

Here is a quick down and dirty on how to get there...
With the 640 card removed...
Plug the 64 gig SSD to the mother board.  Boot and install Windows on one large partition.
When done with installation and driver verification, shut down, Install the 640 card and plug in the four 640 gig drives.
Boot to windows, follow the manual instructions for windows

Set up one large Raid 10 array with the four 640 drives...  You'll get about 1280 GB... Slice it up any way you want...
MARAGONLLCAuthor Commented:
thanks for the reply heideld, I agree with your diagram, and in fact I did install the os on the ssd, and  put the drives into 1 raid 10 array; however, I'm still asking the question for my own knowledge.  Forget about the SSD.   Lets eliminate it out of the picture.

In those scenarios I posted I'm trying to figure out why 1 would perform better than another; or which is the best configuration of the same goal.
As stated before, if your Applications has a io usage pattern similar to your OS, you can just go for 1 single RAID 10 array
Otherwise, having 2 arrays allows for a different array and NTFS parameters more suitable for the applications
MARAGONLLCAuthor Commented:
Thanks for the reponses.  by the way,  while I definately also recommend SSS for os, in case the budget doest allow for an SSD and Just for research purposes I created a support ticke with highpoint.  I gave them the same 3 scenarios and question.   The response from high point in regards to best performance was Option B.  I replied with a question confirming option B and also asking about recovery if the 4 disk raid 0 array failed, would I be able to recovertje raid 1p and rebuild the raid 0 array an reimage the OS or would I need new drives.   I should hear a response tomorrow and post it.    I will split the points between both of you once i hear back from high tech.  Thanks again for your input.  I'm open to Hear your takes on option B.  
MARAGONLLCAuthor Commented:
Sorry for typos above, via iPhone..
RAID 10 is 1 array, so there is no difference chopping off 80GB for OS or putting it all together performance wise.  The OS and data still need to share I/O.  I agree with an above post and would not move the OS from the SSD.
MARAGONLLCAuthor Commented:
Thanks remmett, but note that Option b is 2 arrays raid 0 and 10 on the same drives and controller.
MARAGONLLCAuthor Commented:
thanks for responding guys, I am splitting the points between BigSchmuh and heideld; however, I'm leaving the solutions as partially.
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