Messages in this thread | | | Date | Tue, 26 Jun 2007 16:22:45 +1200 | From | Graeme Sheppard <> | Subject | Re: Patent or not patent a new idea |
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Neil Brown wrote: > ??? > (reads original description in more detail). > > So... the filesystem images are identical in both copies, and the > "interesting" bit is that the image is just a file on some filesystem. > > So could I implement your idea by: > > dd if=/dev/zero of=/1/bigfile count=lotsandlots > dd if=/dev/zero of=/2/bigfile count=lotsandlots > losetup /dev/loop1 /1/bigfile > losetup /dev/loop2 /2/bigfile > mdadm -C /dev/md0 --level=raid1 --raid-disks=2 /dev/loop1 /dev/loop2 > mkfs /dev/md0 > mount /dev/md2 /space > > ?? > > Why would you bother? Well, I do it a lot of code testing, but I > would be hard pressed to make a case for that sort of config in > production.
Thanks for the brief howto there. I'll install the mdadm suite and experiment. It seems like a userspace driver?
> You said: >> 1) the disks need >> not be the same size or from the same manufacturer; 2) the supporting code >> would be cross-platform. > > md/raid already works happily with different sized drives from > different manufacturers (for raid1, it only uses as much space as the smaller > drive provides, For raid0 it uses it all). > I don't know what you mean by '2'.
2 meant in the way that a driver for a PC raid card is not much use on a Sparc.
> So I still cannot see anything particularly new. What am I missing?
I think it's what I missed. Thanks for the heads-up. If the above is a good technique it could suit me well.
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