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qeldroma
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Joined: 17 Oct 2002
Posts: 370
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 Posted: Tue Dec 17, 2002 3:05 am Post subject: Questions about IDE-RAID.. |
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I got the Highpoint 370 controller and compiled it in the kernel.
At startup, he finds it, it should be RAID 0 (striping).
But when i try to access /dev/ataraid/disc0/disc for partitioning, he tells me, that there are 80 GB?!
Though one disc's got 40 GB, he should show up 40 GB, because of RAID 0!!
What is the fault? I tried with cfdisk.... |
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rtn
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Joined: 15 Nov 2002
Posts: 427
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| Posted: Tue Dec 17, 2002 3:30 am Post subject: |
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If it's two 40G disks in a raid0, you DO have 80G.
If it's two 20G in a raid0, you have a problem. 
--rtn |
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qeldroma
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Joined: 17 Oct 2002
Posts: 370
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| Posted: Tue Dec 17, 2002 11:55 am Post subject: |
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Oh, looks like i missunderstood because of mirroring 
Had mirror (RAID1) before, didn'T change my thinking. There is only the half left (from the total amount)... |
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Caviel
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Joined: 18 Nov 2002
Posts: 22
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| Posted: Thu Dec 19, 2002 12:06 am Post subject: |
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Here's some quick info on IDE RAID array types
RAID 0 is striping, and uses two drives. It gives you speed because it takes two seperate drives and makes them into one array by alternating sectors between the two hard disks. The array also is twice the size of the smaller drive between the two, so two 40GB HDs in RAID 0 will get you one faster 80GB array. A 20GB and a 40 GB will net you a 40GB RAID 0 array with the extra space on the 40GB unused.
RAID 1 is mirroring with two disks. The secondary drive in the array is an exact duplicate of the primary drive. You don't gain any speed, as a matter of fact you tend to lose speed when writing to the array, but you gain reliability. You don't gain any space, so two 40GB HDs in RAID 1 will yield a 40GB array. The secondary drive MUST be as large as the primary drive, with any extra space on the secondary going unused.
RAID 0+1 is Mirrored/Striping, and requires 4 drives. This is essentially a RAID 0 setup, with a backup drive for both stripped disks. 0+1 is the most expensive setup since it requires so many drives, it's the best of both worlds for speed and safety. |
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qeldroma
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Joined: 17 Oct 2002
Posts: 370
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| Posted: Thu Dec 19, 2002 11:26 am Post subject: |
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Hm?
I thought Raid 1+0 requires 3 drives, one mirror, two for speed... |
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nomoore
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Joined: 14 Dec 2002
Posts: 15
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Installing Gentoo
