performance - dd dsync results extremely slow. Is this normal? -

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i investigating slow application issues new hardware , running odd results. trying determine causing behavior.

 using :

dd if=x.b1 of=x.b10 bs=8192 oflag=dsync of 101mb file 

  simulate how our database writing disk (the dsync flag suggested our database vendor), , while normal dd commands without dsync option showing 80-100 mb/s, dsync command getting results in 160kb/s-200kb/s range.

this behavior has been viewed on multiple pieces of hardware, different model hard drives , doing drive wipe test:

dd if=/dev/zero of=/dev/sda bs=8192 oflag=dsync

shows more expected 80-100mb/s speed, seems suggest in our custom os slowing things down. have run these tests under custom suselinux oracleos (32 , 64 bit) , continue see these low numbers.

can give me ideas of problem is? thanks


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