What IDE channel and Master/Slave for the third HD? Confused.

MichaelD

Lifer
Jan 16, 2001
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Subject line may be a bit confusing; here's the deal. I have a Abit KT7R mobo. I'm going to be setting up RAID array. That uses up the two IDE channels on the raid controller, leaving me with the two regular IDE channels.

I have a CDR and a CDRW. Currently, each of them is a master on it's own IDE channel. Zero coasters and I'd like to keep it that way.

After I get the Raid array up and running, I'd like to keep my old HD physically in the system for backup/reload/safety purposes.

Problem is that I'm out of IDE channels. Putting both CDRs on the same channel (cable) is out of the question; asking for trouble doing that. But you guys know that already.

So what do I do?

1. Put the CDRW on it's own channel and HD master/CDR slave on the other?
2. CDRW on own channel/CDR master and HD slave on the other?
3. Just get a PCI ATA-100 card and put the HD on that?
4. Punt?


Thanks.
 

NelsonMuntz

Golden Member
Jun 14, 2001
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Michael, it doesn't matter too much what you do with the extra hard disk. With a raid controller you have several viable options. Two that you haven't considered here are to put the extra drive as slave on one of the RAID controller channels. You can do this and not add it into the array that has the other two so that it will not affect the array's performance. that is probably what I would do if given that situation.
 

MichaelD

Lifer
Jan 16, 2001
31,528
3
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Really? I did not know that. I have not considered anything like that, b/c I didn't know I could do it (Duh, Mike!)

Just to clarify, I don't have a big old RAID card, I'm using the onboard raid on my mobo. It only has two IDE connectors.

Please explain a little more, Nelson. I appreciate your time.

EDIT/ADDED
If I can do as you say and put the 3rd hd as slave to one of the masters on the array, would I have any problems copying info from the 3rd drive to the array? Say like, if for some reason the array gets corrupted and I want to ghost from the 3rd one to the array to restore it? THanks so much.
 

NelsonMuntz

Golden Member
Jun 14, 2001
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Mike, it depends on what kind of array you are going to set up. When you set up the RAID arrays you should have the options to utilize up to four devices on the two slots. It is advised that the two drives in a RAID 1 array be on separate channels to prevent a problem with the array if one of them goes bad. If you are doing this for speed (RAID 0) then if either of the drives in the array gives out the whole array is toast. Basically, you should be able to have it as slave in either case without a problem. If a RAID 0 array goes south you're kind of screwed anyway, but if you are using RAID 1 you should be able to disconnect just the bad drive (and maybe change the jumper setting on the thrid drive) and you will have access to the two remaining drives until you get a new drive to replace the defective one.
 

LarryJoe

Platinum Member
Oct 22, 1999
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Whether you go Raid 0 or 1 if one of the drives goes bad, I believe you will be able to get at the other with some fiddling required in Raid 0. It is not that both drives will fail if one does, it is just that you won't be able to see the good drive under Raid 0. If this was the case, I believe you just need to get in the box and move the good hard drive around or switch to Raid 1. I may be wrong here, so don't flame me!

That said, I see absolutely no reason you should not put the 2 CDR/RW's on the same chain. I have my TDK and Pioneer as Master and Slave on the Primary IDE and have yet to make a coaster.

LJ
 

NelsonMuntz

Golden Member
Jun 14, 2001
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<< Whether you go Raid 0 or 1 if one of the drives goes bad, I believe you will be able to get at the other with some fiddling required in Raid 0. It is not that both drives will fail if one does, it is just that you won't be able to see the good drive under Raid 0. If this was the case, I believe you just need to get in the box and move the good hard drive around or switch to Raid 1. I may be wrong here, so don't flame me! >>


Not to flame you or anything, but the way RAID 0 works is that it recognizes the two drives as one with double the capacity of the smallest drive. The increase in speed is accomplished by breaking up files larger than the stripe size into multiple files and putting every other piece on each drive. This means that if you had a stripe size of say 1 Mb and a file that was 2 MB it would split it in half and put half of it on each drive. The reason this is faster is that you have double the bandwidth to two drives on two separate channels as you to one. The problem with it is that if you lose one drive, half of the data for that file is not accessable which means you can't use it.
 

MichaelD

Lifer
Jan 16, 2001
31,528
3
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Thanks NelsonMuntz your time and expertise are appreciated. You don't see me losing any performance with having that third drive as a Slave on one of the RAID channels?
 

LarryJoe

Platinum Member
Oct 22, 1999
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NelsonMuntz - thanks for taking me to school here. Very informative and concise. Obviously, I have not delved in RAID yet (so I probably should not be commenting on it huh?) but am very interested. Not to muck up this thread, but two questions:

Is Raid 0 significantly faster than an ATA66 single hard drive?

What is a good PCI RAID controller?

Thanks,

LJ
 

Palpatine

Senior member
Jan 23, 2001
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Raid 0 performance is nearly double that of a single drive because there's twice as many read/write heads since there are two drives. I'm running it at home and I love it.

If your motherboard won't do raid, you might consider a card like the Promise FastTrak100.
 

MichaelD

Lifer
Jan 16, 2001
31,528
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Really need to bump this. Does NE1 agree/disagree w/Nelsons suggestion? I want optimum performance, that's why I'm going w/RAID 0 in the first place. Thanks. (Nelson, you 'da man...but I do like to get more than one opinion. Thanks :))
 

NelsonMuntz

Golden Member
Jun 14, 2001
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Sorry for the delay I was away for a while, but Palpatine is right. RAID 0 will give you twice as many read/writes. As for the original question and where to put the third drive, I guess since you will mostly be writing to and reading from the third drive from the RAID array and you are going to run RAID 0, it would be best to put it as slave on one of your two IDE controllers because then it won't be pipeline limited by being slave with the array. If you were going to be burning CDs from data on the third disk then it would be better to have it on the RAID controller. See what I'm getting at? BTW, no problem and happy to help in any way I can.
 

MichaelD

Lifer
Jan 16, 2001
31,528
3
76
NelsonMuntz,

Yes, I do see what you're getting at. Thanks very, very much! Guess I can kill my other thread...

I appreciate you taking the time to educate me and answer my questions. Have a great day. See 'ya in the forums! :)