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Recently I did hdparm on my Ultra5 box with one standard hdd on-board |
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(hde), one ATA66 hdd pluged on an IDE expansion card (hde). Result given |
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below. |
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One question: why all of my other boxes (all my boxes using default |
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value for hdds) shows "buffered cached read" speed, but this box |
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"O_DIRECT cached read"? |
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I googled around and tracked some mailing list arguements, it seems |
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O_DIRECT is just another mode than "buffered", which is very close in |
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performance (said so by a hacker on year 2001), and I could just keep it |
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as is. But I just put this question on the list in case I am wrong and |
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could get knowledge from experts ^_^ |
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sappho zhangweiwu # hdparm -tT /dev/hde /dev/hda |
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/dev/hde: |
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Timing O_DIRECT cached reads: 576 MB in 2.00 seconds = 288.00 MB/sec |
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Timing O_DIRECT disk reads: 66 MB in 3.04 seconds = 21.71 MB/sec |
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/dev/hda: |
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Timing O_DIRECT cached reads: 576 MB in 2.00 seconds = 288.00 MB/sec |
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Timing O_DIRECT disk reads: 20 MB in 3.30 seconds = 6.06 MB/sec |
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