On 2/2/2014 12:53 PM, Phillip Susi wrote: > On 02/01/2014 05:39 PM, Stan Hoeppner wrote: >> It's not possible >> to accurately measure IO throughput doing buffered writes. Thus >> O_DIRECT is needed. > No, you can get there just fine with buffered IO as well, unless you > have an obscenely fast array and very slow ram, the overhead of > buffering won't really matter for IO throughput ( just the extra cpu ). Please reread my statement above. Now let me restate that as: Measuring disk throughput when writing through the buffer cache isn't a measurement of disk throughput as much as it is a measurement of cache throughput. Thus, such measurements do not demonstrate actual disk throughput. Do you disagree? -- Stan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
