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Wierd RAID question

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September 7, 2006 4:03:56 PM

I have 3 HDD's

1: 74 gig Raptor
2: 74 gig Raptor
3: 150 gig Raptor

Motherboard: Gigabyte GA-G1975x

Now my question:

Can I do a RAID 0+1 configuration?

HDD's 1 and 2 in RAID 0 While HDD 3 in RAID 1 (for HDD's 1 & 2)

so basically if HDD's 1 & 2 are RAID 0 they essentially become a single HDD at 148 gigs. and the single 150 is big enough to cover them both.

So before you automatically so "No this isnt possible", I would like to hear a genuine answer

Thanks
Kyle

More about : wierd raid question

September 7, 2006 9:06:59 PM

Even if you could, the results would probably be poor because the performance of the single drive would be much slower than the performance of the RAID 0 array. Any documentation will tell you that you need four drives for raid 10.
September 7, 2006 9:28:08 PM

RAID 0+1 or 1+0 is stated to require 4 drives.

However it may be possible if you have 2 partitions on the 150GB.

Why don't you try it and tell us?
(Regardless, performance will probably suck when compared to a 4 drive setup.)
Related resources
September 7, 2006 9:34:28 PM

RAID has nothing to do with partitionss.
September 7, 2006 10:15:18 PM

There are some high-end server controllers on the market that support nested arrays/containers. One of those controllers might be able to do it.

But I would wager than any consumer-level RAID controller embedded into a motherboard is not going to be able to do it.
September 7, 2006 10:19:15 PM

This guy has 2 HDDs, 2 RAID 0 partitions and a number of partitioned storage drives.
http://www.techimo.com/articles/index.pl?photo=149
He does note that hardware controllers may not be able to do this.

How else can Intel pull off MATRIX with 2 HDDs and RAID 0 and RAID 1 if they can't use partitions?
September 7, 2006 11:46:38 PM

Quote:
There are some high-end server controllers on the market that support nested arrays/containers. One of those controllers might be able to do it.

But I would wager than any consumer-level RAID controller embedded into a motherboard is not going to be able to do it.


He is right, but what Nobly is looking at is software raid. You can raid partitions with software, but you need the required about of partitions required the same as there are disk requirements. Controllers look at the physical disk to create logical arrays.

But nothing would be gained here if you manage to set this up. In the "theory" of raid and how data flows, you'd be dumbing down that Raptor to DMA 66. Why not just get a backup agent or image your drive as you go. Better yet keep all your files on the straight 150 Raptor in case your array of raid 0 fails, you have a image and your data.
September 8, 2006 12:12:49 AM

Quote:
This guy has 2 HDDs, 2 RAID 0 partitions and a number of partitioned storage drives.
http://www.techimo.com/articles/index.pl?photo=149
He does note that hardware controllers may not be able to do this.

How else can Intel pull off MATRIX with 2 HDDs and RAID 0 and RAID 1 if they can't use partitions?


MATRIX is a specialized application and isn't "normal" raid. Normal RAID level are defined at the drive level. There are some Intel controllers that support it in hardware but it's nonstandard, and I wouldn't rely on it.
September 8, 2006 12:36:05 AM

Quote:
MATRIX is a specialized application and isn't "normal" raid. Normal RAID level are defined at the drive level. There are some Intel controllers that support it in hardware but it's nonstandard, and I wouldn't rely on it.


In the strictest sense, all RAID controllers are "nonstandard". 8) Each manufacturer has their own scheme of how the drives are identified and physically set up at the block level. This is why you can't take two drives that were in a RAID configuration from, say, a Promise controller, and hook them to an LSI controller and expect to see the defined RAID volume.

Intel Matrix RAID is just a unique way that the controller operates, but it is still defined at the drive level. The Intel Matrix controller can use 2 drives, and set up both a RAID 0 and a (separate) RAID 1 volume on the two drives. Those two RAID volumes then appear as two drive letters to the machine/OS, one of the drives is now mirrored and the other is striped.

It's true that it's nonstandard, but so is all other RAID. It also happens to be very useful. You can have a RAID 1 mirror for your system/boot drive (and keep important data there, fully protected), while at the same time having a very fast RAID 0 volume for applications or video editing, etc. All while using only 2 drives, not 4 as would be required with a different RAID controller.

As far as the partitions are concerned, yes, FredWatson is correct when referring to hardware RAID. RAID in hardware is done at the hardware level, before any file system ever comes into play. Essentially, a RAID controller abstracts the physical drives that are attached to it from the computer's BIOS. The computer's BIOS sees a virtual/logical device that appears to be one large drive, regardless of how the controller has implemented it behind the scenes (RAID 0, 1, 5, JBOD, etc.) On that one large drive, it is then partitioned and formatted at the file system level, which is "above" the RAID hardware abstraction level. This is why you can use hardware RAID with any OS and any file system - Windows/NTFS, Linux/ext3, etc. To any OS, the RAID array just looks like a single large blank hard drive.

Software RAID is another matter. The operating system is performing the functionality of RAID using standard partitions on standard drives. The abstraction is being done in the driver software, not in RAID controller hardware. The computer hardware in this case still sees two physical drives, as does the operating system (i.e. Disk Manager). But the file system driver is combining two physical partitions on two physical drives into a single logical/virtual drive letter.

Software RAID could be used in combination with the motherboard hardware RAID controller to achieve a RAID 0+1. Use the motherboard hardware RAID controller to make a RAID-0, then use dynamic disks/mirroring in Disk Manager to achieve the mirror by using the RAID-0 virtual device as one drive and the larger physical drive as the second drive.
September 8, 2006 12:49:49 AM

If you layer hardware raid for the two 74s with software raid for the resulting 150GB volume with the 150GB drive, it would probably function but be no faster than a two drive RAID 1 volume. Still, if you're looking for redundancy and you need 150GB, it's weird but it should work.
September 8, 2006 1:35:49 AM

WOW,thanks for all the input!!!! Now I just have to sort through this and figure out what it all means since I am new to raids.

anyone want to come over and set it up for me? j/k :) 

Thanks for the help!!!!!
September 8, 2006 6:08:14 PM

Sure we'll set it up if you give us the 150GB raptor :p 
September 8, 2006 7:24:02 PM

Quote:
Sure we'll set it up if you give us the 150GB raptor :p 


haha :wink:

I think I decided to go the easier route and get two more Raptor 74's. and use the 150 for storage.

Now I just gotta get 2 more raptors....anyone got one to sell? :) 
September 18, 2006 3:19:25 PM

Hi there all at forumz, very glad to have found your entry regarding raid set up's. I have a asus p5wb delux and am just about to start building in the next few days. I have 2* 250Gb WD Caviar sata 2 16mb cache Hard drives. I have a choice of setting them up as raid 1 using the asus ez-backup sata ports, or alternatively I am considering using the 2 disc combined raid 0 and raid 1 setup that you discussed, via the intel matrix controller. What ever the solution i would like to have a partition reserved for os [xp] & possibly second partition for 2nd os [vista] , while a 3rd partition would be for remaining programmes and save files etc.

The big question is If i go for the straight raid 1 im guessing that this should not be to complicated, i just set up the raid array, using the asus drivers, then create the partitions - [i guess i would have to create a boot disc on floppy ? ] then install the os to partition 1 and the programmes etc to partion 3 [subsequently installing vista in partition 2 when it is released]. This would give me 1 drive with 3 partitions and a 2nd drie with an exact mirror of this. Should either drive fail, i can just use the mirror drive and rebuild array by swoping out the faulty drive - no real down time. If the motherboard goes bang, i can upgrade to any current [sata2 supporting] motherboard and just plug my hard drives in and they should be ready to roll. This seems a reasonable approach. gives me the safety.

The alternative is to explore the intel matrix combined raid 1 & raid 0 on 2 discs [yes 2 discs]. Besides the not knowing the actual step by step process to do this [the motherboard hand book only mentions this feature in passing], my concern is will i be able to set up 3 partitions, as the above example, my thinking would be that 2partions the partion 1 os1 [xp] partion 2 os2 [vista] and key data would be mirrored and partition 3 raid0 would have on my games and programmes. So giving me the speed increase for gaming. So to my questions

1) can this be done ? ie raid 1 and raid 0 and 3 partitons.
2) if hard disk goes bad can new disk be introduced and the mirror raid be rebuilt [being 2 partions out of 3] the 3rd stripped partion would be lost obviously.
3)if motherboard goes bang im guessing i will have to replace with motherboard with another that supports intel matrix controller, so limiting my choice of boards - who knows amd may have taken the lead back in processing power?! and im not sure they will have intel matrix chips onboard ??
4) Will this be a totaly harware raid 0, and show any significant increase in gaming speeds ? or is there some software involved that will negate the increased read times of the striped drives?

5) Last and probably most importantly, would the raid 1 and raid 0 combined setup be as robust, cf (smiple raid1) in terms of how software auto installs, virus scaning, registry cleaning etc etc.. im really not to familiar with the hierachies involved, nor the intricacies of these various subsytems.

At the end of the day i want my computor to work reliably more than for it to be super fast. Would really value your perspectives as you seem to be far more knowledgable than myself in these matters

Cheers

Ade.
September 18, 2006 5:50:53 PM

Quote:
1) can this be done ? ie raid 1 and raid 0 and 3 partitons.
2) if hard disk goes bad can new disk be introduced and the mirror raid be rebuilt [being 2 partions out of 3] the 3rd stripped partion would be lost obviously.
3)if motherboard goes bang im guessing i will have to replace with motherboard with another that supports intel matrix controller, so limiting my choice of boards - who knows amd may have taken the lead back in processing power?! and im not sure they will have intel matrix chips onboard ??
4) Will this be a totaly harware raid 0, and show any significant increase in gaming speeds ? or is there some software involved that will negate the increased read times of the striped drives?
5) Last and probably most importantly, would the raid 1 and raid 0 combined setup be as robust, cf (smiple raid1) in terms of how software auto installs, virus scaning, registry cleaning etc etc.. im really not to familiar with the hierachies involved, nor the intricacies of these various subsytems.


1. Yes. RAID logical volumes have nothing to do with partitions. The Intel Matrix storage controller can support 2 logical RAID volumes, each implemented at a different RAID level (0 and 1, or 0 and 5, 0 and 10, or 5 and 10). On each logical volume, you can define any partitioning scheme you want. You can have 4 primary and multiple logical partitions on the first RAID logical volume, and 4 primary and multiple logical partitions on the second RAID logical volume if you want.

2. Partitions don't get rebuilt, RAID logical volumes do. If one physical drive goes bad, replace it, and any redundant RAID logical volume (RAID 1, 5, or 10) will get rebuilt, including all partitions that were on it. RAID 0 logical volumes are lost and will have to be redefined and repartitioned.

3. Yes, the physical drives will be set up such that they'll only work on the Intel Matrix storage controller. Replacement motherboards will have to have that. However, that's the case with any on-board RAID controller. On a separate card, you could move that to a new motherboard, but frequently the interface may change (i.e. a PCI card with a new motherboard that only supports PCI-e), in which case you're in the same boat.

4. Yes, it will be totally hardware RAID 0 (and RAID 1, 5, and 10). There is, of course, performance differences between the Intel RAID controller and other controllers from Promise, LSI, etc. Each manufacturer has strong points and weak points, as well as entry-level models and high-end models. I will tell you that the Intel Matrix storage controllers (ICH7R and ICH8R) are considered entry-level RAID controllers, but they are not software-based nor host-based. Now, as to the other question of whether the RAID 0 will improve gaming performance, that's a matter of much debate. 8) My experience (limited with gaming) has suggested that there will be at least some performance increase, but the amount of increase is highy dependent on the particular game and other factors.

5. Provided there are no hardware problems (overheating, bad cables, bad motherboard, bad hard drives, etc.), the RAID setup is just as reliable as anything else.
September 18, 2006 5:55:35 PM

Quote:
Hi there all at forumz, very glad to have found your entry regarding raid set up's. I have a asus p5wb delux and am just about to start building in the next few days. I have 2* 250Gb WD Caviar sata 2 16mb cache Hard drives. I have a choice of setting them up as raid 1 using the asus ez-backup sata ports, or alternatively I am considering using the 2 disc combined raid 0 and raid 1 setup that you discussed, via the intel matrix controller. What ever the solution i would like to have a partition reserved for os [xp] & possibly second partition for 2nd os [vista] , while a 3rd partition would be for remaining programmes and save files etc.

The big question is If i go for the straight raid 1 im guessing that this should not be to complicated, i just set up the raid array, using the asus drivers, then create the partitions - [i guess i would have to create a boot disc on floppy ? ] then install the os to partition 1 and the programmes etc to partion 3 [subsequently installing vista in partition 2 when it is released]. This would give me 1 drive with 3 partitions and a 2nd drie with an exact mirror of this. Should either drive fail, i can just use the mirror drive and rebuild array by swoping out the faulty drive - no real down time. If the motherboard goes bang, i can upgrade to any current [sata2 supporting] motherboard and just plug my hard drives in and they should be ready to roll. This seems a reasonable approach. gives me the safety.

The alternative is to explore the intel matrix combined raid 1 & raid 0 on 2 discs [yes 2 discs]. Besides the not knowing the actual step by step process to do this [the motherboard hand book only mentions this feature in passing], my concern is will i be able to set up 3 partitions, as the above example, my thinking would be that 2partions the partion 1 os1 [xp] partion 2 os2 [vista] and key data would be mirrored and partition 3 raid0 would have on my games and programmes. So giving me the speed increase for gaming. So to my questions

1) can this be done ? ie raid 1 and raid 0 and 3 partitons.
2) if hard disk goes bad can new disk be introduced and the mirror raid be rebuilt [being 2 partions out of 3] the 3rd stripped partion would be lost obviously.
3)if motherboard goes bang im guessing i will have to replace with motherboard with another that supports intel matrix controller, so limiting my choice of boards - who knows amd may have taken the lead back in processing power?! and im not sure they will have intel matrix chips onboard ??
4) Will this be a totaly harware raid 0, and show any significant increase in gaming speeds ? or is there some software involved that will negate the increased read times of the striped drives?

5) Last and probably most importantly, would the raid 1 and raid 0 combined setup be as robust, cf (smiple raid1) in terms of how software auto installs, virus scaning, registry cleaning etc etc.. im really not to familiar with the hierachies involved, nor the intricacies of these various subsytems.

At the end of the day i want my computor to work reliably more than for it to be super fast. Would really value your perspectives as you seem to be far more knowledgable than myself in these matters

Cheers

Ade.

Hi, you may want to start a new thread, you'll probably get more replies.

But i'll try to answer a few of your q's.
1) can this be done ? ie raid 1 and raid 0 and 3 partitons.

I'm not that familiar with MATRIX in practice, so I don't know if that will work.

2) if hard disk goes bad can new disk be introduced and the mirror raid be rebuilt [being 2 partions out of 3] the 3rd stripped partion would be lost obviously.


I'd guess you'd lose the RAID 0 of the MATRIX, since there's no way to rebuild it (no redundancy). But the RAID 1 part would be fine.

3)if motherboard goes bang im guessing i will have to replace with motherboard with another that supports intel matrix controller, so limiting my choice of boards - who knows amd may have taken the lead back in processing power?! and im not sure they will have intel matrix chips onboard ??

Probably would be ok if you went w/ a new intel & MATRIX board. If you switch to another RAID controller, all bets are off.

4) Will this be a totaly harware raid 0, and show any significant increase in gaming speeds ? or is there some software involved that will negate the increased read times of the striped drives?

Gaming speeds are not terribly affected by RAID 0. You might (emphasis on MIGHT) see faster loading times but only by a few percentage points as stated above in the thread. RAID 0 is build for sustained transfer rates. If you want decreased read times, go get a raptor or something.

5) Last and probably most importantly, would the raid 1 and raid 0 combined setup be as robust, cf (smiple raid1) in terms of how software auto installs, virus scaning, registry cleaning etc etc.. im really not to familiar with the hierachies involved, nor the intricacies of these various subsytems.

No difference. What you say about software is mainly on the OS level. RAID is on a lower level and wouldn't make a difference. Not really sure what you mean about more 'robust'

Ack, somejoe beat me to it! But that's good since he seems to know more about MATRIX than me :) 
September 18, 2006 9:35:49 PM

Thanks guys, the internet sure is a fine thing! I really appreciate you spending the time explaining things. If im reading you both correctly the raid protocol is something that varies between vendors [ie there are no fixed standards] i guess a small part of the drives must store these parameters, but surely a raid 1 (pure raid 1, on 2 drives that is) would consist of the main drive and any of its partions in addition to the small part of the drive that holds the info about the raid 1 setup, the other drive would just be a 100% copy of the first. The point im trying to get at is that surely the bulk data would be readable on any future implementation from any vendor, ie they may may not recognise the "raidness" of the disk [any one individual disk, lets say] but would be able to recognise all the data on it [apart from the raid config data]. So if im thinking along the right lines i could take any 1 of my raid disks and hot swop it into a new motherboard [if i needed to upgrade] and use it as a stand alone disk. Then subsequently i could use a new blank hard drive and set that up to mirror the disk from my previous build, [using the new mobo raid protocol]. This is all at the limits of my knowledge so if im talking tosh! then feel free to let me know.
What do you think. What im after is the abililty to take all my data from my new build [the next few days] and be able to use it in any future upgrade /rebuild etc. So if i have it set up as raid 1 or raid 1 +0 , then would i be right in my deduction that i could use any 1 disk in the manner described above as a solo disk? [with the caviat that i would loose data stored on the stripped section - if only taking one disk - here im thinking worst case scenario that 1 disk dies]


Be good to hear your thoughts!

Also if i go for mirror raid 1 alone, would you recommend doing this via the 1 intel matrix raid controller or going for a duplex set up with 1 drive using intel and one using the JMicron B363 raid controller, thus providing security even if one controller fails? [i read on a forum that this is the prefered methodology of implemenation of raid 1] and is this easily done ??

Would really appreciate your input.

Many thanks

Ade.
September 18, 2006 11:23:44 PM

Quote:
The point im trying to get at is that surely the bulk data would be readable on any future implementation from any vendor, ie they may may not recognise the "raidness" of the disk [any one individual disk, lets say] but would be able to recognise all the data on it [apart from the raid config data].

...

Also if i go for mirror raid 1 alone, would you recommend doing this via the 1 intel matrix raid controller or going for a duplex set up with 1 drive using intel and one using the JMicron B363 raid controller, thus providing security even if one controller fails? [i read on a forum that this is the prefered methodology of implemenation of raid 1] and is this easily done ??


You'd think it would work that way, but it doesn't. :?

The one thing that is standard across PCs is the way that a hard disk is accessed and partitioned. Every PC OS, to find data and partitions on a hard drive, reads the Master Boot Record stored at track 0 sector 0. Some of the last bytes in that sector are the disk's partition table, which shows where partitions begin and end on the drive and what type they are.

But when a RAID controller puts drives together in an array, they store different data in track 0 sector 0. There is no Master Boot Record, there is no partition table. Thus, if you take a drive that was used in a RAID implementation and put it on a regular disk controller, you won't see any partitions, no data, no nothing. No ordinary PC disk controller can read a drive that has been used in a RAID array.

So the answer to your question is no, you cannot take a single drive from a RAID-1 array and stick it in another computer and read it. The drive will look blank, or have an unrecognized partition on it.

You cannot set up a (hardware) RAID array spanning multiple controllers. The controller itself is responsible for performing the redundancy functions of the RAID array, therefore one controller must operate all disks in the array. The only exception to this are some high-end SCSI PCI-X controllers that have the ability to span the array across multiple controllers, but even that requires some assistance from a software driver.

Software RAID within Windows can span disks across multiple controllers, but the boot drive cannot be a software RAID, only data drives can use this function.

If you're worried about a controller failure or upgrade possibilities, then you need to purchase a PCI/PCIe RAID controller that can move to a different motherboard.
September 19, 2006 12:06:07 AM

I agree w/ what somejoe said.
I'd worry more about my HDD's failing than the controller.

Anyways, if you have a good backup system (which everyone should), you shouldn't worry terribly about losing your HDD's.

Also, if you're planning on putting a HDD into another computer, you'll probably end up reinstalling Windows, etc anyways. Its not as easy as it sounds because of drivers for the new hardware, etc. Its possible, but its not really worth the hassle.

You kind of sound like you want a full HDD image on another HDD so that you can easily keep going if your primary HDD fails. If that's the case, some kind of imaging/ghosting application may be better for you than RAID 1.
September 22, 2006 10:29:30 AM

ok guys thanks for all the help, I think i now have a much better idea of what i should be doing! Ive realised my understanding of raid 1 was slightly confused with backing up data.

So I think my chosen solution will be to go for a raid 1 setup, with drive using 4 partions.

Partition 1 [primary partition] - os1 xp
partition 2 [primary partition] - os2 vista
partition 3 [not sure what kind of partition]- programme files + save data
Partition 4 -[not sure what kind of partition]- Ghost image and save data backup

Combined with a routine [mothly /weekly] backup of save data to cdr and ghost of system to partition 4. This should give me a balanced security of hard drive failiure, viral attack, system errors caused by badly scripted downloads.

I would really value your opinions if you think the set up im suggesting will work ok, if anyone has any knowledge about potential problems [dual boot set up's, running multiple partitions - does this slow system down ? etc] would value your comments, also what kind of partitions should 3 & 4 be ?

Many Thanks

Ade.
!