El dom, 14-09-2003 a las 19:48, lorne escribi�: > On Sunday 14 September 2003 08:00 am, diego wrote: > > 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... > > > One thing everyone need to remember is that the IDE raid solutions that are > available right now aren't really raid as most have come to expect raid. They > use cpu processor power. This puts an extra load on the processor. The scsi > raid systems have their own on board raid processing power. I currently use a > mirrored system and was disappointed with performance. I'm happy to stay with > it though, so if I lose a drive I haven't lost data. So if you are thinking > pure peformance, you should probably not use the cheap typical ide raid. > There are some more expensive ide raid controllers that do ues real hardware > raid though. I just don't recall any off hand. What I remember from the HowTo was just the opposite: as splitting data blocks in 2 / joining them is trivial calculus really very little CPU was used even with a full-software raid 0. That's why the howto recomended software driven raid (standard, HW independent, reliable and easy to update/upgrade to new functionalities).
> > > > 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. > > > ---- > > Want to buy your Pack or Services from MandrakeSoft? > Go to http://www.mandrakestore.com -- Diego Dominguez __/\__ | | Andalucia / \ Spain \ / |__ __| \/
Want to buy your Pack or Services from MandrakeSoft? Go to http://www.mandrakestore.com
