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On 06/11/2014 12:21 PM, Stefan G. Weichinger wrote: |
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> Am 11.06.2014 13:18, schrieb thegeezer: |
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> |
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>> just out of curiosity, what happens if you do # dd |
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>> if=/dev/vg01/amhold of=/dev/null bs=1M count=100 # dd if=/dev/sdc |
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>> of=/dev/null bs=1M count=100 |
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> |
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> |
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> booze ~ # dd if=/dev/vg01/amhold of=/dev/null bs=1M count=100 |
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> 100+0 Datensätze ein |
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> 100+0 Datensätze aus |
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> 104857600 Bytes (105 MB) kopiert, 1,71368 s, 61,2 MB/s |
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> |
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> booze ~ # dd if=/dev/sdc of=/dev/null bs=1M count=100 |
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> 100+0 Datensätze ein |
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> 100+0 Datensätze aus |
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> 104857600 Bytes (105 MB) kopiert, 2,40518 s, 43,6 MB/s |
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> |
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> |
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ok baffling. |
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sdc i already said would be slower but not this much slower |
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it certainly should not be slower than the lvm that sits on top of it! |
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i can't see anything in the cgroups that stands out, maybe someone else |
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can give a better voice to this. |
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all i can think is there is other IO happening |
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in atop if you can highlight any line that begins LVM CPU or DSK and |
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paste it in to a reply - with no virtualmachines running and no dd or |
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anything. |
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then run a dd as before and highlight the lines in atop while it is |
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running (maybe increase count to 1000 to give yourself a chance) and |
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paste in here too |
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