Digital BW, The Print

Alan Kearney wrote:

This is interesting.  Given the choice between RAID 0 (also known as
"striping", because data is "painted" in "stripes" across the disk
drives) and RAID 1 (also known as "mirroring"), I generally choose
RAID 1 for enhanced reliability.

From a reliability perspective, RAID 0 creates a single disk out of
two, and a failure in either disk drive effectively breaks both.
Roughly speaking, this makes the system storage somewhat less
reliable than a single disk.

RAID 1 creates a single disk that can tolerate a failure of either
disk, which makes the system storage more reliable than a single disk.
Depending on how clever the RAID implementation is, a RAID 1 volume
can provide somewhat better read performance than a single disk and
somewhat slower write performance.

> The RAID 0 that I use takes 2 identical drives and spreads the data across
> the 2 drives when writing to the drives and reads from the 2 drives when
> opening a file. The gain here is speed, the computer can access the files
> MUCH FASTER because the system doesn't have to "hunt" as much on one drive
> for the pieces of any file. Defragging the drive(s) is as simple as if you
> only had one drive, in fact only one drive appears when you open "My
> Computer".

You should see about 2x the performance of a single drive.

> Is it "really worth the time/trouble to set it all up?" , absolutely! The
> only "trouble" involved is having the RAID controller and as Alan A.
> mentioned most motherboards come equipped with one. The only other concern
> is the 2 drives have to be the same size and speed. I'm not sure if they
> need to be from the same manufacturer but getting a matched pair would
> eliminate any problems you might encounter.

Generally speaking, you shouldn't need identical drives for RAID 0, since
you're just stitching them together.  Even RAID 1 shouldn't have a problem
with two different drives - it just won't be able to use part of one drive
if it's larger than the other.

> And lastly, if you're building a desktop system you've no problem with room,
> I've a pair of 80 gig drives in my laptop!

500GB SATA drives are now cheap enough that a desktop really should run a
pair of them in RAID1 if possible.  Performance will be comparable to a single
disk and reliability will be substantially better.  It's like maintaining a
back-up all the time.

Dana