Ron,

You can get the answer and that is by running a benchmark, or locating some
benchmarks.

My experience with installing raid 1 on servers is that I am impressed with
their performance, reliability (of the raid mechanism itself - the raid 1 is
self apparent), and ease of setup (Intel ICH5R).

With the Intel ICH5R controller - from experience - it is an absolute
breeze: It does everything as it should. If you get a drive failure, you get
a flashing icon on the task bar (the intel documentation is crappy in the
extreme). Rebuilding a broken array is automatic - just don't delete the
array or fiddle with the config (ever). Notification options are needed:
email is in my view essential, along with Event Log records since a flashing
icon requires you to be at the server to see it (or use terminal server).

I would have no qualms about raid 1 at all. If the performance is not good
enough, then consider the more advanced IDE / SATA raid controllers that are
out. Some include raid 5, cache memory, and increased drive connectivity.
While it is certainly true that raid 1 requires 2 x writes, both writes can
occur at the same time. If both drives are healthy then responses are
received by the controller in close succession, so the elapsed time for a
write is about the same as per a single drive, not twice.

Toms Hardware ran a review on one of these recently and as they do, gave it
their thumbs up.

If the performance is not good enough, but you still need that extra data
assurance, then I would suggest Raptors or SCSI with or without raid. SCSI
drives are substantially more reliable. Ultra 320 SCSI RAID 1 with a caching
controller is brilliant (and a little expensive).

Raid 0 is high risk - the probability of a logical drive failure is
multiplied by the number of drives in the RAID 0. IDE drives seem to be
dropping in reliability, so this is only good for scratch data EG video
editing.

At the end of the day, I suggest you look at the value of your data, your
charge rate, the cost of an outage or loss of data and ask yourself: How
much would I be willing to spend to prevent an outage or loss of data of say
1 day. If you earn $1000 / day (lets hope) then that is what you should
spend. If it took 5 days to recover lost data, then you should consider
spending more - get an AIT tape drive or something.

Final Note: I had 2 drives in a mirrored pair die the other day. First drive
was 100% shot, second came up with 1 bad sector (no earthquakes or anything
like that). The customer was *very* lucky and got everything back. This does
happen, so make sure you have good backups too.

- Tim







"Scotter" wrote in message
...
Hey Ron -
Thanks for your response.
However, my question has nothing to do with striping. I tried striping
long
ago and like you say, I found it to be too dangerous.
My question here is this:
Will I take a performance hit by going raid (mirroring) using two drives
vs.
just no raid at all with one drive. In other words, when the raid
controller
splits the data to write to two devices instead of one, is there a
performance hit?
Thanks!
Scott

"Ron" wrote in message
news Hmm. Well, yes, sortof.

I say "sortof" because if you haven't run for awhile on a RAID0/striped
array...THEN switched to RAID1...you won't have a point of reference
against
which to compare the performance [decrease] of a mirrored array.

Is a striped array faster than a mirrored array? Absolutely. But as you
already know, the latter is safer.

That said - and I know there are those that disagree - my counsel would be
to go with the RAID0. The likelihood of a failure on one out of two
drives
which are in a RAID1 array is still pretty slim. And if the failure of
one
of those two drives ends up taking 2 years...then you will have lost out
on
the significant performance boost offered by a striped array for 2 years.
A
bit like buying insurance, eh? You just pay your price; just in case.
Except in THIS case, a failure means a bit of time to re-install software,
not a loss of life. Besides, if you set up a striped array, you can
always
maintain a clone of the array on a separate drive in the system!

Please post a follow-up.
Ron