El dom, 14-09-2003 a las 11:25, Anne Wilson escribi�:
> On Sunday 14 Sep 2003 12:32 am, diego wrote:
> > El s�b, 13-09-2003 a las 22:45, Anne Wilson escribi�:
> > > I thought of scsi2, but it's very expensive, so it would have to
> > > be worth a lot more. I planned a 7200 120GB disk. It would have
> > > very little on apart from the needs of the job.
> >
> > Have you thought about raid? Maybe you can try with that ide drive,
> > and if too slow get a second one to form a raid 0 (cache speed
> > would be the same, mantained speed about double).
> >
> I've never worked with raid. From what I've read I came to the
> conclusion that lower levels of raid were not worth bothering with,
> and higher levels too expensive/complicated. I'm willing to hear
> that I'm wrong, though.
That's not true, I'll show the most interesting cases in brief. Let say
you have a HD and it's running out of space, so you buy another one.
Then you'll have some programs/data in one and some in the other, but in
general you are only accessing one at a time (what a waste!! ;-)
So what Raid 0 (raid for speed) would do is (for example) define a
virtual HD that has a sector of 32K when actually each drive has exactly
the half, so it reads/writes data joining sectors from both drives. That
way you have the same capacity as in the paragraph before but now with
the time a drive needs to give you a block you get 2. Useful, isn't it?
The drawback is if one of both fails, you won't loose half the data but
ALL!!
Raid 1 is for reliability as it writes exactly the same data in both
drives, so even having 2 drives you have only 1 drive capacity, but if
one fails, you still have ALL the data.
Raid 5 is a situation where you have N+1 drives (minimum 3) where you
have N for speed (about N times faster than a single drive) and the
other one for reliability. Actually all of them work together for speed
and reliability, so a drive (ANY drive) may fail and you'll still have
ALL data.
ALL of them are trivial to set up (if it seemed trivial to me... well
you know ;-) Anyway, I'd go for Raid 0 in your case as:
1) it's cheap
2) you'll get a 'virtual HD' about 2 times faster
3) doing backups are easy and cheap, so if one of the drives dies you
won't loose all your data...
>
> > If thinking on a fast AMD XP, just have a very close look at the
> > heatsink+fan as it easily maybe insufficient or be too noisy...
>
> That could be very important. I'll make sure I get recommendations
> from my supplier for efficiency and noise.
>
> Before I actually order anything I shall make a composite document
> with all the recommendations I have had from everyone, so that I take
> maximum advantage of everyone's experiences.
>
Depending on how close you will be to that computer, noise will be a
factor. If you're going to be close to it many hours, take one with less
than 30dB of noise.
As your future CPU seems it's going to be near 100% many hours, cooling
power is esential.
I recently bought a "Aerocool Deep Impact DP-101" and I'm quite happy
with it, but get more info from the real experts...
Good Luck with the project.
--
Diego Dominguez
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