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Help w/ Compact Flash raid

Last response: in Storage
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November 27, 2002 1:11:25 PM

Hello all,

I have three devices capable of reading compact flash cards, and three 128mb compact flash cards. Given this information, the obvious thing to do is, of course, set up a software-based compact flash striped raid array. I realize my present interface (USB 1.0) is a huge bottleneck, but with the right interface (firewire), and enough cards, I think I can produce a storage solution that rivals, even surpasses the performance a low end hard drive from 1996. With this in mind, I pushed forward with USB 1.0, simply as a proof of concept. The operating system is Windows XP Pro. The three devices are a PDA, a digital camera, and a flash card reader. The flash cards are high quality cards produced by Mr.Flash. With everything hooked up, I went into XP's disk manager. This is where I ran into problems. I have administrative rights, and I'm a generally nice guy, but Windows XP still refuses to let me delete partitions on these devices. No deleted partitions means no software raid. I really feel like I'm on the edge of greatness. Can anyone advise me on how to proceed?

Thanks,
Ken

More about : compact flash raid

November 27, 2002 6:49:40 PM

Quote:
and enough cards, I think I can produce a storage solution that rivals, even surpasses the performance a low end hard drive from 1996

You will need a LARGE stripewidth in order to obtain that kind of performance. The best Compact flash cards I have seen are able to read about 4MB/s and write about 3MB/s. Even with the theoretic maximum performance of a RAID0 array you will need a stripewidth (number of CF cards) of at least 10 to get just 40 MB/s. In reality you will probably only get 30 MB/s. This is an extremely expensive solution compared to an average modern harddrive.
Further USB 1.1 only provide 12Mb/s (thats Mega BITS) or about 1.5 MB/s, which will completely nullify any attempt to increase performance using a RAID array.

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