from Raid 0 with 2 drives to Raid 0 with 3 drives

WinWiz

Junior Member
Jul 2, 2001
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I have a system with 2 80 GB HDs in Raid mode 0
I wanna add a 3rd 80 GB HD so that i get 240 GB. My Promise Fasttrack "Lite" controler only support 2 HDs so i have flashed it with a "hacked" BIOS. My Problem is that i cant backup 150 GB (my HD is almost full), so i wanna know if i can add a 3rd. HD without deleting all my data?
 

opk

Junior Member
Oct 29, 2002
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In a word, no.

The nature of the RAID is that it sets up everything beforehand. Your system only sees one big 160MB volume. The raid controller sets up (in the case of raid 0) stripes across the drives. Right now you have every other stripe on every other drive. In a raid 0 across 3 drives, it's every3rd stripe on every 3rd drive. It's in no way expandable.

 

earthman

Golden Member
Oct 16, 1999
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How do you get 240G in raid 0? You would only have the 80GB no matter how many drives you had in that configuration.
 

opk

Junior Member
Oct 29, 2002
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RAID 0 is the one that's not really RAID as it's not Redundant. It's a stripe set across multiple drives. The benefits are (with 3 80G drives) 3x the storage space (240G), a slight read/write speed improvement and (usually) more efficient use of you IO bus. Ths downside to RAID 0 is that if any of the drives fail, the entire volume is hosed.

The soln to the original problem is either to find a way to back up the 150G already on there and build a new stripe set, or live with 2 volumes one 160G and one 80G.

 

TheCorm

Diamond Member
Nov 5, 2000
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Raid 1 is Mirrored then I think......isn't it better to have Raid 5 with 3 drives....Parity & Mirrored is that?....but of course you gotta have the raid controller that supports it.

If you have a Raid controller that only supports Raid 0, 1 & 0+1 then can you make efficient use of 3 drives?
 

opk

Junior Member
Oct 29, 2002
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On my RAID controller (IDE) i have up to 4 drives.

I can use RAID 0 w/ 2, 3, or 4 drives efficiently using all of them by striping across all drives into 1 big one.
I can use RAID 1 with either 2 or 4 drives to mirror either 1 or 2 individual drives onto 1 or 2 more for security while wasting half of my capacity.
I can use RAID 0+1 with 4 drives to stripe across 2 of them and then mirror that stripe set for security. You get one big drive, but still waste half the space on security.

Past that requires a more expensive controller/more drives. Tom's Hardware has a good primer on RAID (IDE RAID specifically) somewhere on the site.
 

Buzzman151

Golden Member
Apr 17, 2001
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How do you get 240G in raid 0? You would only have the 80GB no matter how many drives you had in that configuration.

Wow... I don't think you should be giving anyone tech advice. Anyways... OPK is right.... there is NO way you can do that. Nor will you get 240 gigs... you'll loose a couple gigs in setting up the array. What I did while reformatting my RAID drives was used a spare to have a copy of XP, some of my extra data, and then i put the rest of my data on my friends computer. I then formatted my array w/ the extra HD that I had from Widows. Its hella easier that way and you can change the stripe size of your format.
 

earthman

Golden Member
Oct 16, 1999
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Thank you, but I actually do know what I am talking about, I just assumed he was striping as well. Doens't make sense to do it any other way, you greatly increase your risk of data loss, and contrary to popular belief RAID 0 is not that much faster. I think Anand's did a comparision of these types a while back.

RAID 0: Also known as 'striping', this is technically not a RAID level since it pro-vides no fault tolerance. Data is written in blocks across multiple drives, so one drive can be writing (or reading) a block while the next is seeking the next block. The advantages of striping are the higher access rate, and full utilization of the array capacity. The disadvantage is there is no fault tolerance - if one drive fails, the entire contents of the array become inaccessible.

From Cutting Edge RAID basics, and I agree.
 

Smilin

Diamond Member
Mar 4, 2002
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Ouch. Better to be thought a fool than to open your mouth and remove all doubt.

3x80gig *IS* *approximately* 240gig when used in a RAID 0 array (which is the exact same thing as stripping). There is no configuration of any raid type that I'm aware of other than a triple Raid 1 array that would give you 80gigs of space from three 80 gig drives. Raid 0 is SIGNIFICANTLY faster than a single drive. It is in the ballpark of 190% as fast (w/ a 2 drive setup).

WinWiz:
No way to do it man. By definition your drive is going to get scrapped when you change from a dual to triple stripe. I have to ask you man: how you going to feel when you lose all that???. 2 drives in raid 0 is risky but not bad with todays drives, but 3 and you're starting to ask for it...ESPECIALLY using a hacked controller. You've come this far, why not get one more drive and a good raid 5 controller?
 

DAPUNISHER

Super Moderator CPU Forum Mod and Elite Member
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Aug 22, 2001
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WinWiz, what block size did you choose? just curious :)
 

opk

Junior Member
Oct 29, 2002
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I ran RAID 0 for a while (2x40G). The throughput was faster (almost 2x). I mainly did it to have a cheaper 80G drive tho. I'm not a speed freak at heart, and the thought of all my digital pics sitting there so percariously got to me. I bought a new 80G drive and swapped everything over.

That's the best solution BTW. just buy a new 160G or 200G drive and forget about RAIDs anyway. Mine was just an experimentto see what it was like, but RAID 0 is just asking for it anyway.
 

Buzzman151

Golden Member
Apr 17, 2001
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i guess it all depends if its worth the risk. If you have yourself some good HD's, you really don't have htat much to worry about. I have the WD 120 SE's running RAID 0 w/ a 32k stripe size. I'm VERY happy w/ them. Plus, alot of times, you're drives will give you a hints that they're gonna fail; usually making noises. This happens alot of times but not all.
 

Lorne

Senior member
Feb 5, 2001
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If you already have the extra drive then add it to the main onboard controller as a back up drive.
Put all the stuff you dont use on it and if the raid gets hosed your extra drive will be safe.
 

JustinLerner

Senior member
Mar 15, 2002
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Originally posted by: opk
In a word, no.

The nature of the RAID is that it sets up everything beforehand. Your system only sees one big 160MB volume. The raid controller sets up (in the case of raid 0) stripes across the drives. Right now you have every other stripe on every other drive. In a raid 0 across 3 drives, it's every3rd stripe on every 3rd drive. It's in no way expandable.
As opk and Smilin said, RAID 0 is in no way expandable. Don't use a hack unless you don't care if you loose your data. RAID 5 is expandable, but that's not what you have.

If you are using Windows 2000 or XP there is another option.
For better reliability, don't use hardware RAID 0, but use NFTS symbolic links with basic disks, not dynamic disks (for backup and restoration issues, dynamic disks are hard to work with).

When using symbolic links, there is the ability to assign a drive to any empty directory/folder (not a drive letter) and any subsequent access to that directory/folder actually correlates to the newly assigned drive/partition. The number of drives and symbolic links in Windows 2000/XP is unlimited (not limited by drive letters).

This may be a better way to store your stuff. Only use RAID 0 for temporary fast storage/access (like video editing, movie making) or for uniportant data, like games or sofware which can always be reinstalled.