ACF888 wrote:I think you may be on to something with regards to the oflag=direct setting.
The I/O speed fluctuations I'm seeing is due to caching from our NFS storage side.
I spoke with an Oracle consultant, he said to use:
dd if=/dev/zero of=test.img bs=1M count=1000 oflag=direct
If using oflag=direct, then you're using the direct IO bypassing the buffer cache. I used both with and without oflag=direct and am getting around 10-13 MB/s.