Read-Only RAID-5 on DVD? :-)

[James Gray]

On 3/7/06 12:02 PM, "Wisely Koh" <wiselykoh at gmail.com> wrote:

> I am positive someone did raid with diskette drives, saw it on digg
> some time ago...

Don't top-post.

Yes, I've seen a RAID5 using 5 USB floppy drives in action.  It's slow, but
it's faster than a single floppy - fantastic for curiosity and
"coolness"...beyond that it floppies are just far too small and slow to be
of any practical use.  I've personally made a RAID4 out of a couple of CF
cards which was relatively fast (RAID4 is basically RAID5 except with a
dedicated parity drive, rather than distributing it - this reduces the
"damage" to a single card...flash media has a finite number of write cycles
before the "sector" goes bad).

However, a floppy (or CF card) is NOT analogous to a CD-RW or DVD+/-RW. One
has random read/write the other has linear (sequential) write and random
read.  You CANNOT create a RAID5 on devices that can only support sequential
writes.  Period.

If you wanted to make a RAID5 out of DVD's it wouldn't be a "true" RAID5,
rather it would be some sort of seriously hacked ISO9660 format.

HTH,

James