RAID question

[RichL]

I'm hoping someone here has tried this and can give me the lowdown.
I'm thinking of getting a motherboard with onboard RAID, or an external RAID card, and running a pair of drives as Raid 0 (striping).
The question is, when striping, do the physical disks have to be identical in size, or is it just the logical volume size that has to be the same?
Can you utilise the non-Raid'ed portions of the disk(s)?

[HomeBrewer]

No. They don't HAVE to be the same physical size, but the resulting volume will be only twice the size of the SMALLER disk.

[Gurm]

Actually, it really depends on the implementation. My FastTrack IDE RAID will allow non-identical volume sizes, and will give you most of the space. For example, striping a 40GB and a 30GB will get you roughly 70GB (probably around 67 actually).

BUT, it won't be as fast, since it'll not be a 1:1 interleave anymore. It'll be a 4:3 interleave.

- Gurm

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Listen up, you primitive screwheads! See this? This is my BOOMSTICK! Etc. etc.

[xortam]

News to me Gurm ... that's the first time I've heard of a RAID array using other than symmetrical interleaving. I guess that's a nice option if you have to maximize your capacity with a mix of drives. Usually, people run RAID to protect from drive failure by providing redundancy. Myself, and many of us desktop users, like to run RAID 0 (which isn't RAID) to provide maximum throughput. The best way to optimize your RAID performance is to buy identical drives or at least drives with the same performance metrics (capacity and seek/access times).

[Gurm]

Yeah, I didn't think it would work either, but the Promise will do it.

It DOES really hurt performance though.

- Gurm

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Listen up, you primitive screwheads! See this? This is my BOOMSTICK! Etc. etc.

[RichL]

Thanks Gurm.
I just have one more question -
If I had say, a 30gb and 40gb disks, and partitioned them as 30 & 30 for a Raid 0 array (Drive C), could I use the 'spare' 10gb on the second hdd as Drive D, or is it unusable as long as the drive is in a Raid array?

[Gurm]

Unusable.

- Gurm

------------------
Listen up, you primitive screwheads! See this? This is my BOOMSTICK! Etc. etc.