PATA + SATA drives in RAID array

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I was running two 80GB maxtors on the PATA side of a promise controller and getting read scores in HDtach around 90mb/s. Now im running 3 drives in the array, one being a SATA drive, and the scores dropped to around 30mb/s, a single drive scores around 70mb/s. I tried striping sizes of 128 and 32 and neither seemed to make much difference.
Has anybody else setup arrays with both PATA and SATA drives?
Are my scores low because there are only 3 drives? I plan on adding a 4th drive soon.
Or are they low because Im mixing SATA and PATA drives?

thanks
jason

 

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ttt

 

[Zelmo3]

Are the spindle speeds all the same?

 

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all three drives are dimondmax 9+ drives..

Im starting to think that the problem is with an odd number of drives, because it seems as long as all the drives are the same speed the type of connection shouldnt matter. But, i wont know for sure until i get the 4th drive. If then the speeds come up I'll know it was the odd number causing the problem, if not.. I wouldnt reccomend mixing PATA and SATA drives..

 

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For those who care or are curious, or might want to know in the future..

The three drive array appears to be flawed. I recreated the array (several times) with only a PATA and SATA drive and was able to achieve typical two drive results. I did find out that if a 16k stripe size is used the 3 drive array will perform similar to a 2 drive array but yielding the extra capacity.

Cant wait to get the 4th drive..